Curved sharpening stones - Page 1
Forum section: electronics / general

author: KL27x
author_rank: Super Contributor
timestamp: February 18, 2020, 10:34:23 pm
content: I've had some discussions last year that were related to this. Some thing about the burs, and how to get sharp edges. Ebastler comes to mind. I don't remember who else was involved. This is also something maybe my buddy coppercone2 might like to see, based on some of his past posts.I finally made a video. I don't have a YT "channel," and I'm not trying to make one. I have a job, fortunately, seeing as my YT channel has only 1 subscriber (Does YT automatically give you 1 subscriber for yourself? I have no idea why I have a subscriber, at all. I've never published anything on this account).Anyhow, this is just a video I made to show some convexed stones and a quick demo on how I use them. Requested by some random folks on reddit. But they asked nicely enough. I don't talk in the video. My sinuses are messed up, my jaw is too big, and my tongue is two sizes too fat for my mouth. So I don't talk in the video, but I added some captions. I spent a couple hours at least, making it. I thought I'd at least share it with 3 more people, here.https://youtu.be/Pjfv1gRGtQMOh, the request was specifically just to show what I was doing. So maybe a tiny bit of background.The curved surface reduces the contact area of the hard (non slurry/lapping stone). This increases cutting:burnishing. This make the soft arkansas sharpen, efficiently, without making bur, and without dulling the stone over time. I never had to do anything to these stones to maintain them. No flattening, no silicon carbide power, no microbevelling. This produces and/or maintains a razor edge without any other stones and makes a hard edge every time. You can't overdo it and soften your edge. The stones maintain shape by how I use them, no extra effort involved. (As long as I don't have to sharpen a pile of drill bits or 1/4" chisels at a time).

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: February 19, 2020, 07:35:08 pm
content: Where can one buy such stones? I can't seem to find anything like this in the UK.

author: Gregg
author_rank: Super Contributor
timestamp: February 19, 2020, 08:32:28 pm
content: Here is a very interesting video with electron microscope pictures of burrs etc.https://youtu.be/RkYrpFGS5bY?list=PLFA60459F187488EFPersonally I find the Wicked Edge sharpener the best I have found (but it is pricey)https://wickededgeusa.com/

author: KL27x
author_rank: Super Contributor
timestamp: February 19, 2020, 09:05:49 pm
content: QuoteFirst off, I'm thankful that anyone posted anything at all, to this. I was resigned to having put out a matza ball for which no one cares. So thanks for that, Ralprmartin, Gregg. And T3s, thanks for the thanks.Answer: I don't think you can buy an arkansas stone like this from a store. (And I highly recommend soft arkansas stone for this).What I did was buy some diamond plates for $4.00 each from Ebay China. I suggest 240ish the way to go for a soft ark. Then you use your eye.People today stress out over how do you make sure it's "perfect?" There is no perfect. The stone will take the shape of how you use it. And the only reason (IMO) that it is curved in the long axis, at all, is just maintenance. If you take a stone nearly flat (or even flat) in the long axis, and you try to maintain the shape like that through use, your margin of error is tiny before the natural wear causes localized dips. If you start with enough curve for that material and how you use it, you will have the same error/tolerance in how it wears, but that shape you are aiming to maintain is curved enough where you don't get dips or "reverse curves" in the stone through this margin of tolerance/error. It is off by just as much, but it's still positively curved, everywhere.As Jarrod says, "there's something magic that happens when every part of the stone can positively touch every part of the bevel."If you curve the stone too much (I have experimented with that), what happens is you just end up using a smaller area of the center of the stone, because your wrist/arm/overall-movement range is not enough to use that whole curve efficiently. And the stone will wear down to the flatter shape, naturally. You're just getting it roughly into shape with the diamond plates. It's not, as we say, rocket science!A 240 grit diamond plate makes quick work of the soft ark. Not a big thing. Just do it under running water.This is really awesome for knives, esp. Because when you do the belly to tip, you start on the side of the stone and end up on top. That follows the edge automatically. You don't have to chicken wing your elbow out to follow that curve. It's like using a rod, but one where you have more area on top to not round off the tip.This curve doesn't make the arkansas magically able to do anything, though. On blade with a large enough bevel area and/or hardness of the steel, you will exceed the limits at some point. E.g., I can't do the whole bevel on my 3/4" chisel, for instance; I'm just sharpening the edge bevel of the compound bevel. If I try doing the whole bevel, I can feel the metal start to glide over the stone. In this case, if you feel it's not cutting well, stop doing it! You're wasting your time, and this will glaze the stone, and then you have to do something to get it working, again. Just go to your coarser stone at that point.The other no-so-obvious benefit is that the oil stays on the stone. You don't need as much. When you sharpen a straight edge on a flat stone, you squeegee the oil back and forth. It is messier and or takes more frequent application.

author: ebastler
author_rank: Super Contributor
timestamp: February 19, 2020, 09:21:41 pm
content: Hmm, not sure it was me participating in the original discussion you are referring to, but I am curious now. Would love to watch the video, but Youtube apparently does not know my age, and I like the idea of keeping it that way.KL27x -- any chance you could remove the age restriction on that video?

author: KL27x
author_rank: Super Contributor
timestamp: February 19, 2020, 09:35:02 pm
content: Yeah, sure. I just did it cuz all the warnings YT gave me. I don't think I will get fined for this. Try again in 1 minute.

author: ebastler
author_rank: Super Contributor
timestamp: February 19, 2020, 09:55:30 pm
content: Thank you, KL27x. Watched the video now, and learned quite a bit. (About sharpening techniques, and the fact that sharpening stones can be a collectors item. ;-) But I am not a knife and sharpening afficionado, so it must have been someone else in the original discussion. Hope they find this thread!I very much enjoyed your video style, by the way. Keeping it quiet, with just the work sounds and the text in captions, totally works for me. And you found a very nice balance in the texts, keeping them succinct, but informal and colloquial.

author: KL27x
author_rank: Super Contributor
timestamp: February 19, 2020, 10:20:43 pm
content: I might have been exaggerating a little about that prior discussion, to give me a reason for posting this in this forum.The thread got around to the question of what the bur or wire edge is. It started with the quality of drill bits, and how most of them will have a bur left on the edge, even the expensive ones. I think you were in that thread? You're a machinist by either hobby or trade, no?Collector items? Yeah, I went a little deeper into the rabbit hole than I intended. I got some nice pieces of hardwood for Xmas back when, and wanted to do something with it besides making a box. Which I also did.And thanks for the part of that I will choose to take as a compliment to my handiwork.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 20, 2020, 07:15:09 am
content: You're probably thinking of me. And my big gripe about the video is going to be machinist related. Did you really have to use a precision square to rub against the stones to show convexity?! I legit cringed!

author: tautech
author_rank: Super Contributor
timestamp: February 20, 2020, 08:48:56 am
content: Yes well it's interesting what stones are accepted for each job and while an ordinary flat bench stone is perfectly suitable for the vast majority of tasks yet some will still try and reinvent the wheel.In my inventory of stones all are flat faced and the only ones with curves are curved edge slip stones acquired primarily for deburring outside ground gouges.They're the only stones I use that need oil as they came oil impregnated whereas my main Crystolon/India combo stone lives in water as it's a lot less messy to use.With practice of good sharpening technique a stone face can be kept near perfectly flat and across it if anything it's preferable to have a minute dish especially for sharpening a 'smoothing' plane iron where on wider timber you don't want a perfectly square edge as it leaves lines on the timber. A shooting plane iron OTOH should be wider than the work so it can and should have a straight and square edge.For portable stones my dad used 3" dia round 'spit' stones that you could comfortably keep in your pocket and a juicy spit was all that was needed to use it anywhere at all. He walked everywhere around our land carrying his grubber to grub out any weeds and many of them were woody so keeping a good edge on his tools made the job easier. A knife or an axe got a rub with it too as required. As the edges it was used on were curved it never mattered if these round pocket stones got dished faces after years of work.All this talk about burrs, if the burr is excessive then the edge has been sharpened too far....simple user error yet the forming burr is a sign that the edge is fully sharpened and then the burr can be removed by at least a couple of methods. Razors as many know were finished with a leather strop that served to completely remove the burr by folding it back and forth as well as polishing the new edge even sharper. Tools like a plane iron or wide chisel can be addressed in much the same way however tradesmen that use these sorts of tools have tough coarse hands and a freshly sharpened tool edge can be carefully wiped back and forth along the hand to wipe the burr off.With a stone each side of a freshly sharpened edge can be drawn away alternatively to effect the same process as stropping and folding the burr to and fro.I easily make do with just 2 stones sharpening all manner of edges, only a flat bench Crystolon/India Combination and a radiused edge slip stone.ymmvhttps://www.nortonabrasives.com/sga-common/files/document/Catalog-SharpeningStones-Norton200.pdf

author: KL27x
author_rank: Super Contributor
timestamp: February 20, 2020, 07:08:17 pm
content: QuoteOopsie; eKretz vs ebastler. My bad and apologies to both of you. My hard disc filled up and started to corrupt decades ago.I'm not a machinist by any means, but I do I love my machinist squares. I was mindful to not actually rub them on the stones. But I can see why even that would get your hackles up!Tautech, I agree with everything you said on the surface. And I'm not going say anything to contradict it. I will just clarify that I use india and crystalon, and these (as well as most other synthetic stones) are designed to be used flat. Indeed they work excellent when flat. In fact, the crystalon won't work if you try to convex it. It will just waste and crunch away until the surface is closer to the shape of your blade.In fact, I would be fine with only an india for the rest of my life. It's the only bridge I probably would ever really need between power grinders and a good edge. I think Norton solved the sharpening stone problem what, 70 years ago or w/e. The rest is capitalism.So why? Partly it was curiosity. Arkansas stones (not so much from arkansas, but probably from Turkey and England and other places) were used in antiquity. And it was named the razor stone, or novaculite. I've searched for pictures of old sharpening stones, say from Roman or medieval times, but I couldn't find anything. These guys didn't have Norton india stones to do the actual sharpening, and they didn't have diamond plates to refresh the surface. I imagine if they were lapping the on float glass, there would be some reference to it, somewhere.Also these guys had to sharpen swords and whatnot, longer than the width of a sharpening stone (you would assume, anyhow, lol). Even in Japan, the land of waterstones, I have found that the traditional way swords were sharpened with rounded stones. This has been handed down from the guys who actually did this. Some ancient swords were essentially straight, some even a bit recurved. (Slurry/lappy stones work best IME on straight blades that aren't too long, or even better kitchen style knives with have a gentle curve approaching straight; not so nice to sharpen say a skinny 8" carving knife or boning knife that is very very straight and long. On a flat soft ark, even worse. Bad times. That might just be me.)There is also, according to Jarrod, this idea that all of the cutlery and razor manufacturers in Solingen, Germany, use curved stones to hand sharpen their products for centuries. I won't call that a fact, but this is what he claims is told to him by Dovo workers. And I find it works, with the soft ark, very nicely. Lots of benefit. Some are not so obvious.

author: tautech
author_rank: Super Contributor
timestamp: February 20, 2020, 08:09:00 pm
content: First I should qualify my remarks as a ex qualified tradesman carpenter also with a lifetime of rural living where a decade or two back we had 4 generations all living close by with whose experiences to draw on.It is quite correct other stone styles were used historically for sharpening long blades and as a child I remember an oval one with a wooden handle used for sharpening scythes before the days of even horse drawn hay mowers and even dreams of grain headers.I've ruined a bench stone or two in my apprentice days with incorrect use style and dished them end to end and side to side much of it due to using a honing guide for plane irons and chisels whereas careful handheld technique to use the stone'swholesurface far better preserves its trueness.I also have a very fine natural Arkansas oil stone that is so fine that it's only good for polishing to a keener edge but it's so slow cutting I now hever use it. Also of interest is my grandads cut throat razor mud stone, a water stone and again another that is very fine but also soft so cannot be used for narrow tools as they will dish it badly.Nice discussing these things as it helps share our knowledge.

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 03:58:21 am
content: QuoteThat's what most Americans would think, as well. My first Arkansas stone sat in the bottom of a toolbox for 10-12 years, untouched since the first week after buying it. I had the same thought as you. It was pretty close to useless.But the way our fathers could do anything they needed with just one india stone, I suspect our farther removed ancestors made these novaculite stones do way more than shine a bevel. I bet they were a very good and practical sharpening tool, because they can be; I have proven it to myself. I suspect there are plenty of Dovo workers who would think the same.And if they CAN be, and if there was no Norton, Shapton, etc, then it must have been. The shape and technique changes how the stone functions. Our ancestors weren't worried about messing up their shiny Spyderco. They were sharpening stuff to survive, and their days were too busy to waste time, adding a novaculite stone to some kinda "progression." This was a valued trade item, not a time-wasting hobby stone. They were sharpening, in my imagination, all manners of tools for woodworking. Hoes, froes, adzes and weird stuff we never heard of. Because we have tractors and chainsaws and lumbermills.This is not to say you can't get these stones to sharpen at all when they're flat.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 21, 2020, 04:55:36 am
content: This is a very wide ranging subject. Books have been written about it and not covered all the vagaries. A few notes:India hones have been around much longer than 70 years. I own one that's marked with a 1908 manufacturing date, and it's by no means the first.Very fine Arkansas stones (translucent, black) are meant to be used as a final step in the sharpening process that only just smooths the apex of a blade. They aren't meant to remove much metal.There are many and varied compositions of hone and stone with wildly differing binder strengths. The razor hone that turns to mud is a good example of the softer end of the scale. Black or translucent Arks are a good example of the opposite end. There are several factors that play into which end of the spectrum is better for a certain use - hardness of the material being honed/sharpened, surface area in contact at once, what stage of sharpening, etc.

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 07:16:31 am
content: Hmmm. Ok. Lemme try a logic game.If you assume that this particular tool (i.e. soft ark) is best-suited to this particular niche (i.e. shiny up a bevel, add a microbevel, or cheesegrate/lap-it-to-get-it-to-work-almost-as-well-as-way-better-alternatives-but-use-it-anyway-because-of-tradition) which we have put it in, presumably due to all the new and shinier (and cheaper and/or more profitable?) tools which have been added to our arsenals since at least 1908 or earlier, you might be getting shortchanged.Is this even the traditional way to use it? Or did we invent this practice/methods for some other reason? Such as the invention of the diamond saw making perfectly flat and very nearly rectangular slabs of this stone the easiest way to produce them? Perhaps the first generations to buy these perfect slabs, maybe they immediately "fixed them?" Then a generation of humans grew more fond of the "new car shape" than they had need for this tool to actually be effective?By this time, synthetics might have taken over the market, and these stones might have started to be shelved, anyhow? Or become collector's items?While the true craftsmen in Solingen Germany quietly continue to find this stone to be one of the best tools for hand-sharpening despite all the new and shiny?Despite the time I invested into the fancy wood mounting systems I made, mine are not collector items. Everything there is for utility, once I figured out that these ARE going to be my main method of sharpening, due to being actually more practical for me, all told (well, to be more specific, I mean for blades which require to maintain very keen edges; this method is incredible for maintaining a keen and durable edge, all by its lonesome. Amazing. Not that it makes a sharper edge than other methods). I have used my india only twice in the last 2 years. To sharpen drill bits, and to sharpen a friend's brand new knife that came with no edge. The bits I added were added to get the right height/grip, add utility with the endcaps, clamping points, ergos, et al. That was kinda satisfying in itself; it felt like it was in my DNA to haft stone to wood, like pre-humans have done for like 1 million years or something like that. 700K maybe? I forget what the stone age was.

author: ebastler
author_rank: Super Contributor
timestamp: February 21, 2020, 07:23:12 am
content: Quote from: KL27x on February 21, 2020, 07:16:31 amI‘m afraid they are not that traditional in Solingen. They introduced water-powered wheels a few hundred years ago, and have progressed further since. ;-)

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 07:47:50 am
content: Quote from: ebastler on February 21, 2020, 07:23:12 amWell, notice wheels aren't flat, BTW.But are you suggesting that true modern craftsmen, construction workers, capenters, razor makers, leather workers, butchers, chefs, and tailors, all buy Tormeks and/or send their stuff out to professional sharpening services, now? Or they find that 5 lbs of stones and a pond/bucket and frequent maintenance/flattening to sharpen a 3 oz knife or chisel is the most practical way to get their end results? Or is the power grinder and the Norton india this latest advance beyond the water-powered wheel, maybe? Those are both very useful, those last. Can't not have those, I admit, and they can do double duty to keep keen edges. And I guess you can say the india can replace the soft ark. But there are still advantages to the soft ark. The waterwheel is today the main tool used for shapening, if you count all the disposable stuff we use now. Razors and box cutters and scalpels and exactos, and on and on. There are still people/professions which need to resharpen things, but a waterwheel might not be a recoupable initial investment, nor maybe portable enough for the task! Or maybe not worth the space!I just feel like after trying this, that humans have largely forgotten how to use this tool.

author: tautech
author_rank: Super Contributor
timestamp: February 21, 2020, 08:03:53 am
content: Quote from: KL27x on February 21, 2020, 07:47:50 amWater driven wet stone ? That's a bit flash !All the ones I have seen had a cranking handle....presumably cranked by the baddest child of the day.

author: ebastler
author_rank: Super Contributor
timestamp: February 21, 2020, 08:21:21 am
content: Quote from: KL27x on February 21, 2020, 07:47:50 amI'm not in any of these businesses, of course, but my guess is that what you describe is indeed the case: Craftsmen and workshops either buy a motor-driven grinding wheel (maybe not quite as high-end as the Tormek), or they use an external service. Small or one-man sharpening services are pretty common; some of them are mobile with all equipment installed in a little van, and they run regular routes or visit larger customers on demand.

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 08:31:19 am
content: QuoteYeah, I think they're super common. But play along, here. Specifically in the context of keeping an edge keen? Like when it get slightly dull, the tool is no good? But 20 seconds with a cheap, portable doodad would bring it back? The motor driven whatnot could not do this as fast, even?90% of modern humans probably don't need to do this. To some of these people, this is maybe a foreign concept. That a power grinder, even a water wheel specifically made for super fine honing, is not necessarily convenient/improvement just because it can remove more material faster. On this kind of blades, the grinders are convenient only for occasional use for the rare regrind. At least to the person who has the ability to do this that other way.

author: ebastler
author_rank: Super Contributor
timestamp: February 21, 2020, 08:39:48 am
content: Well, for a quick touch-up of knives, these are very common in kitchens (commercial and at home) over here:https://de.wikipedia.org/wiki/WetzstahlEither steel or ceramic. I assume other businesses use them as well.

author: tautech
author_rank: Super Contributor
timestamp: February 21, 2020, 08:51:33 am
content: Those in trades that I know, more and more use power tools and most use tungsten cutting edges some of which are quite cheap today so the incentive to use tool or HSS steels and the sharpening skills required are such that the skills are slowly being lost. Even using ebastler's argument of using sharpening services is becoming less as the cost of many cutting tools diminish.Time is money so if a tool edge is removed for sharpening it's now more efficient to fit a new one and then only the more expensive cutting edges get sent away for sharpening.Many professions use outside sharpening services, some only to have their tools put 'back into shape' for them to then manage sharpness on a short term basis. Here butchers often use a service to keep their knives in good shape and just steel an edge on them whenever needed.Even the carpenter doesn't use chisels or planes much now as most finishing items like doors are pre assembled and only require fitting to an opening whereas much assembly is done with routers today.

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 09:43:45 am
content: You guys both make very good points.Ebastler, yep. There are many ways to skin this cat. And some will be better for one person's needs than the other. Or maybe it's just a matter of what one knows or has been exposed to, and there's no need to change, because it works. I don't think it's weird that people have gone to other alternatives. I think it's weird that we think the way we use these arkansas stones today (if you believe the internet) was the way they were always used in the past. Because that isn't very useful, at least for a time/era when it was best thing going for a much more significant need. Esp when it is actually extremely good at this other need, even when compared to modern alternatives (IMO, of course), when used in this strange way which is pretty much seemingly unknown, today.Tautech, yep. Saws are disposable. Bits are disposable. The only thing I can disagree is that fitting doors in wooden framed houses and wooden door frames is always going to require chisels rr bull nose planes, at least at some point to someone (ok maybe not the builder of a new house). But otherwise, I'd say you're right on the money.

author: tautech
author_rank: Super Contributor
timestamp: February 21, 2020, 09:46:40 am
content: Quote from: KL27x on February 21, 2020, 09:36:11 amNope, only for fitting the latches/locks and striker plates.Doors are now almost always pre hung and their round corner hinges let in with a router.Yeah, it’s not the fun it used to be !

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 10:19:06 am
content: I kinda meant that at some point, some houses will warp and doors will stick. Or did we solve that with some kind of free-floating door frame?

author: mzzj
author_rank: Super Contributor
timestamp: February 21, 2020, 10:33:33 am
content: Quote from: KL27x on February 21, 2020, 10:19:06 amAt least in here sticking doors are pretty much thing of the past. 40 year old garage door needed adjustment on hinges to compensate for wear but that's about it.Doorframes and doors also come in standard sizes with pre-machined cutouts for locks and striker plates. (or even assembled with hardware)It's either +50 years old building or something gone silly if construction workers/joiner-carpenter needs a chisel.

author: ebastler
author_rank: Super Contributor
timestamp: February 21, 2020, 11:53:10 am
content: Quote from: KL27x on February 21, 2020, 10:19:06 amThat's what builders' foam is for (at least over here).The official license to botch...

author: eKretz
author_rank: Frequent Contributor
timestamp: February 21, 2020, 03:20:42 pm
content: Quote from: KL27x on February 21, 2020, 07:16:31 amErr, that has not much to do with my short statements. For final edge work, a translucent or black Ark is the tool of choice. And yes they have been used that way since they came out of the ground via mining probably the very first time. That's their purpose. And it's because the stone is so hard and dense that it can't really do a lot of cutting. If you lap it very coarsely it will cut faster but it will rapidly dull and the stone is so hard that the dull grit doesn't get removed, it just sits there dulling more and more and you end up with a glazed surface.A Soft Ark is a different animal altogether. These stones are less dense than the aforementioned stones, and when the surface dulls, if a little more pressure is used they will shed dull grit and have new sharp grit ready to cut. If you really want a performer find yourself a Lily White Washita stone.The reason these stones are not used so much anymore is because they aren't much good for any steel containing hard carbides like vanadium carbide or tungsten carbide. These are present in solution in a lot of the newer steel alloys. For plain carbon tool steel (straight razor, old chisels or plane blades, older kitchen knives) they are fantastic. For any modern "super" steel (SV30, HSS etc.) they are mostly useless as the carbides are harder than the silica that forms the stone.

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 05:56:53 pm
content: Yeah, the translucent/surgical is completely different than soft/"hard." I have nothing to complain about the translucent/surgical or the way that they're used today. IMO surgical black/translucent is a burnishing stone, and it is best at being a burnishing stone. When it gets dull and becomes like glass, peeps like that. No one thinks this is a good thing with the soft.QuoteYou assume this is the case. I don't know if that's true or not, TBH. Because I don't have any "super" or crucible/powdered/sintered steels. But.My kitchen knives are very hard stainless steel. This stainless is so hard, I initially used a belt sander to get a profile on this set of kitchen knives. Starting with 36 grit.* (Well, no, that wasn't significantly faster/better than 80; but it was taking so damn long, I tried and used 36 for the start of one knife, and that wasn't too coarse for this; more dangerous to messing up the side of the knife, though, which I did but not too bad). I sharpen a 440C knife. I also sharpen some chrome vandium steel on it. Just a small chisel made from hardened tool steel hex bar stamped C-V? All that jazz is what you assume, or been told, or have read. But maybe 1000 people use this soft ark, and they get 1000 different results. Because of the way we share/teach/learn to use them. Seems like most people end up thinking of them as some mystical, old-timer, nostalgic thing. Which is usually called "very slow and unforgiving, but will payoff with extreme patience." This if far from the truth in my shop and kitchen.Undoubtedly, I understand that the size of the bevel and hardness (or abrasion resistance) of the steel is definitely a limiting factor to ANY abrasive stone which cuts primarily by abrasion (not lapping/mud). Particularly on wide flat bevels, these "super steels" of high RC and abrasion resistance will make a flat stone, esp, "tap out" and skate earlier for the given bevel area in contact with the stone. This is why curving it makes it cut better.************************************************************************************Imagine for just one second, a 2" wide single bevel plane blade on a perfectly flattened non-lapping stone in a sharpening guide. How much area of steel to stone do you have? It's huge! How do you expect this kind of abrasive to work like this, at all? This is like taking a file and laying it flat on your welding table, sliding it back and forth, and expecting it to cut even this soft hot rolled steel when using it in this way. This is similar to having too high a TPI for a cut. The file is harder than the steel, but the geometry doesn't work. Take a flat sanding block with some wet/dry sandpaper, and even better add some oil, and this will cut.* THIS is probably why some people claim that ark can't sharpen A2 plane blades, even. But some people can. We tend to think it's the "quality" of the individual stone. But maybe it's more likely the technique. These A2 "upsell/upgrade" blades also tend to be 50% thicker; this is 50% more bevel surface area.If you think of the soft ark as a very fine toothed file, and you know how to use a file, you might get more out of it. Because it's excellent when used in this way. The finer the file, the smaller the area it can cut. So even after convexing it, there's a limit to what it can handle. But in this case, for most western tools anyway, it can still cut enough to be a sharpening tool, IME.*Does this mean the file is a bad tool for hogging unhardened steel? No. It's the best unpowered tool in the world for removing material from steel chucked in a vice, when that area of removal isn't thicker than what the file will handle. Way better and faster (and more accurate and controllable) and more efficient than sand paper over a sanding block. We still use files because they are the best at what they do, not to save on sandpaper. Context matters. The sloth is way faster than the barracuda when you put them both on land.added: Now if you rub that file on your welding table long enough, there are no shavings, still. But maybe you notice it starts to get shiny? Do you say "wow, now THIS is what the file is for! This is the best and only correct way to use a file! This is great! Files are for burnishing!"*************************************************************************************I might just have to buy a "super steel" to try it and report. But which "super steel?" because I don't really care to buy one let alone more.*edited to add that I used a woodworking belt sander which is way too slow for this. I have never used a proper belt grinder, but I'm sure it would go 4-5x faster at the right surface speed for hardened steel. It's like using the wrong weight hammer for the job. The energy goes into the wrong thing. When you're too slow, here, the sandpaper takes relatively more of the wear than the metal. When you hit the right speed for this particular job, the metal comes off way faster. You will get way more sparks, too. You don't get that huge spark trail on the woodworking sander cuz it's too slow. You get hardly any at all.

author: tautech
author_rank: Super Contributor
timestamp: February 21, 2020, 07:04:35 pm
content: Quote from: KL27x on February 21, 2020, 05:56:53 pmThat is exactly why I stopped using honing guides......say we just want to freshen the edge......which is now a 'face' of a single angle where just a shade steeper honing angle can get the dulling edge back to pristine sharpness.The primary grind and honing angle can be restored later after a hollow grind. Halfway through a job time is money !

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 21, 2020, 07:11:44 pm
content: The skills are definitely going away. Part of the general drop in mechanical skills (at least here in the US). 80-100 years ago we were an agrarian economy. Most people lived on a farm, and farmers have to be jacks of all trades maintaining their own gear at the end of a long slow supply chain. Now less than 10 percent of the population is farming. The rest work in fast food, offices, factories and the like. Only a tiny fraction actually cut things. And those who do use power tools and disposable tools. The utility knife is ubiquitous in tradesmen's tool boxes. When the blade gets dull, turn it around and use the other edge. When that edge gets dull swap in a new one. Or snap off the end and push the blade out a few millimeters.The economics of sharpening just don't make sense. That new blade for a utility knife costs a few cents in bulk. At tradesmen wages there is no way to sharpen a blade for that price. Same kind of things are true at a slightly higher price point for saw blades, drill bits, router bits and the like.Now as a retired hobby person the economics make all the sense in the world. As long as I don't find sharpening drudgery it makes all the sense in the world.

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2020, 07:42:09 pm
content: QuoteI relate to these farmers. I spent most of yesterday fixing my PCB etching system. I let the mud daubers into the NPT connector for the third and final time. Luckily it wasn't a spider, this time. The mud daubers (or w/e it was) stop inside the connector, rather than messing up the inside of the regulator, like the spider. I assume there's some gross larva growing inside that hardened goo, which is probably more what stopped me from just drilling it out, rather than the prospect of cleaning the bit, after.I got the heebee jeebees and suddenly wanted some rubber gloves just inspecting it.I drilled out and tapped the inside of my last replacement fitting to take a 1/4" bolt as a cap.Plugged it in, and nothing. Air lines cracked and replaced. This section of plastic air hose has to be heated and unbent so it stays straight, that there's an art to that without ruining it. This got me wondering if maybe a piece of aluminum tube stuck inside the tube would be corrosion resistance enough, but that's for another day.(I finally noticed after a decade of doing this, that when the bubbles of my cupric tank boil over, exactly why. I just vaguely thought when the cupric turned to cuprous, the bubbles got more crazy. But it's actually when the acid runs out.)Then I spent another 3 hours grind-turning a custom reamer for production use.QuoteThis exact example is actually why I started sharpening. I used to buy exacto and utility blades by the 100 pack. And once I learned to sharpen my knives properly, I swear it is faster to sharpen than it takes to get my replacement blades out and swap them out and to properly dispose of a blade (which for me this involved putting some tape over the edge, at least, before dropping it in my trash can). That little victorinox stone used to sharpen exacto knives is where it first clicked to me, that this is viable for me.added: In hindsight, it wasn't the changing/disposing of the blades that bothered me the most. Once something becomes part of my habit, it's fine. I hated reordering them. Yes, the more you order at a time, the longer between reorder... but the more you forget how to buy more of the good quality and a decent price, and the more it matters you get the right ones. I already found a good one through trial and error and actually caring which worked the best, but that one is not available anymore. Or that seller is gone. And I don't want to investigate exacto blade brands and styles and catalog numbers, again. Because I'm not interested in that, anymore. I already figured that out... oh wait. What I figured out was a brand and a model number and a pricing/availability (and perhaps quality control) in one specific moment in time. And those things change over time (or you forget the bits of data you need to find and buy them). The rock is the same today as it was a million years ago. It will be the same a million years from now. That should cover me for the rest of my life, at least.

author: tautech
author_rank: Super Contributor
timestamp: February 21, 2020, 07:55:38 pm
content: Quote from: KL27x on February 21, 2020, 07:42:09 pmMason bees/wasps we call them here. They paralyse spiders with their sting and lay an egg on them and seal them in a mud cavern for their larvae to consume the meal and then emerge as new wasps to start the next generation.Daupers have been found responsible for blocking the pitot tubes on airliners and then the fight computers and pilots get the wrong airspeed info that leads to crashes.

author: SeanB
author_rank: Super Contributor
timestamp: February 21, 2020, 08:03:06 pm
content: I do tend to dress blades at work, mostly because the as bought edge is not actually sharp, so i will dress it up quickly to have a really decent cutting blade. OK I am not actually using a bought stone, just using what is to hand, either the base of a ceramic cup, or the edge of the mouse pad, a salvaged offcut of Rustenburg black granite kitchen top, which has only a top and front polish, and rough cut sides. It does make a fine mouse mat, does not move at all, very precise, and heavy enough that nobody wants to take it, plus the thickness of the thing is enough to get a disposable blade engaged enough to dry dress it. They come off a lot sharper than out of the box, and then make cutting anything so much easier.At home I use some round aluminia hones, not actually meant to be hones, but what else do you do with a ceramic piston when somebody broke the borosilicate glass bore by careless handling. I call them my thousand Euro hones, as that is the replacement cost from Ceramus.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 22, 2020, 04:53:31 am
content: Quote from: KL27x on February 21, 2020, 05:56:53 pmNo, actually, I don't assume, but apparently you do...I have tried it. More than a few times. I probably have accumulated years if not a decade of linear honing and sharpening time. I often sharpen on something for a couple hours most every night, have done for many years since a couple decades ago when I started using straight razors, trying different stones, hones, steels and techniques. It is a relaxing hobby for me.The "super" steels can not be efficiently cut by silica abrasive. Period, full stop. I say again, the silica is softer than the carbides contained in these steels. A knife just saying "Cr-V" on the side doesn't mean much on it's own. The vanadium needs to hit a certain percentage to make the steel difficult to sharpen. S30V is about where it starts to get pretty tough. Give it a try yourself, the steel will skate right across an Ark stone like it's on glass. Which it basically is. With a very coarse silica based stone you might get lucky and manage to cut the matrix around the carbides and pull them out allowing some small amount of work to be done but the edge will be ragged as all get out and the going will be VERY slow to say the least. These steels can not be efficiently cut with much short of diamond or CBN abrasives. Graduate to a T15 HSS blade and you won't even make much headway with an aluminum oxide or silicon carbide hone.BTW, the file analogy sort of bears out my point. Forget the welding table, would you try using the file to sharpen the A2 plane blade? No, because it's not hard enough to cut efficiently. Same goes for the file vs. the sandpaper against the welding table. The file is nowhere near as hard as the sandpaper's abrasive, so of course the sandpaper will cut better over a large surface area... If you could apply enough pressure to the file while it was flat against the table it certainly would produce shavings. A sharp coarse double cut file probably would produce shavings quite easily. It's a matter of using the right tool for the job and the right technique for the tool at hand.

author: KL27x
author_rank: Super Contributor
timestamp: February 22, 2020, 08:12:32 am
content: QuoteeKretz. I'm treading into dangerous water here, because you're the machinist. So I look forward to your thoughts on this.The file is supposed to be harder than the welding table, in my example. If your welding table is harder than a file, please just imagine a different welding table that isn't. In my country, hot-rolled steel has such low carbon that it can't even be heat treated to begin with. (It has to be, because it is used for structural things. And if it had too much carbon, welds would fail. I think it's spec'ed btn 0.3-0.6%, or maybe that is for common rebar? I can't recall, now). I would guess rc hardness in the 40's, scratching on the 50's at best? Furthermore, let's say the surface oxides have all been freshly ground away, so there is nothing funny on the surface.The file will still slide over the table without cutting. It's because of the geometry. The file was optimized to make quick work of a smaller area of cut on this material. That's what the teeth were sized/shaped/spaced to do. When you try to use the entire face at the same time, it doesn't work. It's similar to having too high a TPI in a cut. You just spin your wheels, and your saw blade will just overheat and dull. No matter your feed rate/pressure, no matter your surface speed, it just won't work. Even if we give the saw infinite beam strength so we can jack the feed pressure as high as we want, well there's nowhere for the chips/swarf to go. The saw gullets will choke on the chips and rub and drag those chips against the stock. That 40 tpi saw trying to cut the 4" round, it needs to come up for air, sooner than that. It can't make that thickness of cut.**The sandpaper doesn't cut because it's harder. It cuts because it starts out uneven to begin with, and particles break off and roll around between your sanding block and the welding table. This second bit is called lapping. And the lapping process can technically cut over an infinite surface area of cutting/contact if you are patient enough, although it will possibly have some practical limit, too. This is even better if you use some oil so you don't lose your abrasive grit.But if you take a 1/4" thick plate of hot-rolled chucked in a vice? I'll take the good file which is optimized for fast removal at this task, over any sandpaper you want. All day, every day. The file will be faster. There's hard enough, and there's harder. OTOH, there's also geometry. Let's say the sandpaper is sharper, because we can use and throw away as much as we want. Clearances. The file has way better clearances by design. The sandpaper has just points that plow throw the material. Rake angle. File by design. Gullets i.e. swarf clearance. File by design (now that it's within its stride). The file will run circles around the sandpaper. The file is now in its element, like the barracuda in the deep sea.Added: The soft arkansas isn't so optimal, of course. It cuts like a bad file, but that's still good enough for what we need in order to make great edges, as long as we use it within its scope or sweet spot. Although it's a bad file, it's still way better as a file than it is as a lapping stone. To lap, you need lapping paste/grit. Finally, even a bad file can potentially still cut faster than lapping, as long as we stick to the right cuts. This is because lapping is inefficient. For the amount of work input, not a lot happens, compared to direct abrasion/filing. A more accurate way to state that in a physical sense might be to say: for the amount of work, a lot more "other things" happen aside from material removal, compared to direct abrasion/filing. OTOH, the lapping stone can be firm (releasing some grit but still pretty stingy) enough to have some of the best of both actions, and the benefit of staying a bit sharper via faster turnover/renewal rate, but a bit less stable/accurate. And this balance can be good effective. These kinds of synthetic stones in their strides are probably the best for a practical balance between speed and work and accuracy, when they are tuned right for your needs.As for the other stuff, I know the ark stone will not be able to work on any steel; and there will be a practical limit. I think curving the stone will increase this band. So now, what kind of edge bevels are we now able to do with these other materials. I think the hardness of the steel is a major factor, itself. I have a chisel made from a file. That file has the original temper. I do not sharpen it on the ark. I don't know if it would work, but it surely won't work well. I can tell by the way it feels, that it is struggling with even a fairly narrow edge bevel. (It was very slow to grind that bevel in on an aluminum oxide belt sander, too.)I still don't know for myself that it can't be effective on "super steels," though. I have no doubt that anything with a very high hardness is not going to fare well. I know some things you said might be super high rc, but maybe others are "super steels" for other reasons? So if you suggest SV30? I might give that a shot. I wouldn't be too sure that these carbides will make that much difference aside from the total percentage increase, I think. The chromium and chromium carbides is a big part of what makes stainless so slow to grind, because that's 13% of the steel. It's a lot. The other stuff is just couple more slightly harder peanuts added to the whole can of chunky peanut butter. Maybe?So I honestly edited the post you are responding to BEFORE I read the above post of yours just now. Just wanted you to read it, and for other people to know what I added, and that nothing was changed to purposely shade your latest post. I hadn't even read it, yet. So this makes your post look weird, and it makes me look triply redundant, now, but I don't know better to to fix it.added 2:18:I had also softened some of my language which might have initially been more provocative. I am not looking for any kind of trouble. This asterisked section has, in my own hindsight, become somewhat of a distillation of many of my ideas, and I was trying to flesh it out, a bit. And to streamline it. And to make it more accessible and as not-confrontational as I could, while keeping to my train of thought. This is why I had edited it, in the first place, just for whoever few people might read it for the first time (or again). I didn't know this would have happened.Quoteedited:Regarding the supersteel/SV30?So ideally, I would want to try a steel which is chock full of these vitamins C and V and w/e other chunks you like in there, but which is not going to be heat-treated as hard a file? I'm thinking 63-65 tops? But the lower, the better.*Ours is a completely different appreciation of sharpening, BTW. I want the process to be sweet, but also short. All jokes aside.So I'm looking forwards to the critique from a machinist. If I got something wrong here, I will grateful to know where I've tripped up.;;;;;;;;;;;;;;;;;;;;;;;;*Looking at the price of these things, my enthusiasm for this experiment has wained just a little. So if you can suggest the exact brand and model you have the experience and hopefully still have, so i can have the same apple as your apple, that would be nice. And now I see it is S30V, not SV30. Oops.** edit: Imagine if you had to cut this 4" round of mild steel using only your horizontal saw and you have only an endless and free stack of these 40 tpi blades. But the world depends on this. So you would eventually cut through this steel with this saw. And the way you'd do it is to stop and rotate this round in the vice every several seconds, at first, to target the next high spot where you can get your foot in the door, again. You would be cutting small sections of chords approximating a radius or a curve. Just nibbling off the high spots as you go off that wheel of cheese. At first this will be really slow going. But as you get closer to the center, and that radius decreases, you can cut longer between adjustments. (Because the polygon's # sides of fixed chord length, the length where the saw stalls, is decreasing; the angles of the polygon are decreasing, and the rate at which the cut thickness increases with the depth will decrease.) But I digress. When sharpening, we can't curve some of our edges away from the stone by nibbling it into a radius, because some of these edges need to be straight. We con convex the bevels in order to reduce the cutting area. Compound bevels, same idea. But there a major multiplication of surface area to stone when we put any straight blade onto the flat stone. So we can curve the stone away from the bevel.To most people of our era, that would sound stupid. If you leave it flat, the stone will just burnish more and "act like a finer grit," right? But it's a fundamentally different tool. You can't put on or even maintain a good edge when you're burnishing too much. Even if you do it longer, you will make an apex, but that edge will not be as hard; this is where you can cut some of that schmoo off with a microbevel, and hope to get to the crunchy center. But if you want to learn it, you can get a better edge than that off the soft, directly, and to sharpen very quickly. Not just finish. Or course if you want the burnishing at the end, you would go to a different stone for that.

author: coppercone2
author_rank: Super Contributor
timestamp: February 23, 2020, 05:22:38 am
content: i dont want to think about mechanical things for a long while but restoring blades and drill bits makes sense because its basically factory new and the restored system is not working in a degraded state.shipping materials are already a big enough disposal fee from dealing with cardboard so it makes sense, fuck thinking about how much it will cost you to cut a box open or put a hole in something, thats always better free. its a stupid ass microtax, i swear i hallucinate little parking meters on boxeswith knives the only problem is that you need a spare in rotation so you don't cut yourself when you are excited and need it to open something or prepare food etc, so it can be sharpened at the right timei swear it makes the price of a pizza pie double because you need to deal with the stupid box and stupid pizza box related problems (its a pest shelter so it must be destroyed). I kind of wonder if you can roll up a pizza box ,but then it starts costing you duct tape. it might as well be a truck suspension

author: KL27x
author_rank: Super Contributor
timestamp: February 23, 2020, 08:04:25 am
content: Bout time you dropped by, Copper! What are you on vacation?Good to see ya.

author: coppercone2
author_rank: Super Contributor
timestamp: February 23, 2020, 08:14:15 am
content: Quote from: KL27x on February 23, 2020, 08:04:25 ammassive clean up and accumulated broken shit repair

author: coppercone2
author_rank: Super Contributor
timestamp: February 23, 2020, 08:17:48 am
content: awg2020, rackmount telemetry set, solar system, battery gadgets, old pc, sorting 8 shoe boxes worth of fasteners, researching crimps/tools, cable management, etc.

author: KL27x
author_rank: Super Contributor
timestamp: February 23, 2020, 06:11:08 pm
content: Tending the ranch, jah. Nuther day, another sorrow.But about these fancy rocks sharpeners, I'm still on a roll, here. Gotta excorcise these demons.Warning: for the crazy knife people, only:;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;BURR REMOVAL.The curved stone also seems to aids with peeling off the burr. The first time this really hit home, I remember quite well. But the story starts earlier.The experiments started small. The little Victorinox soft was probably the first. It's barely more than 1.5" long. And shortly after making it, I had the habit of sometimes carrying it around in my pocket. Mostly just to remind myself that it was there. But I had an occasion to sharpen a friend's chef knife with it.Some days after this, I noticed the grooves I had made in the stone. This was a 7 or 8" chef knife which had never been sharpened before, so it took a little while to do, standing by the sink, using a drop of dish soap and water. This might have been the first opportunity to sharpen a factory edge in my convex stone education, aside from the tiny blade on a multitool. So this was a bit of an opportunity for me.The bevel has the vertical striations left by a grinding wheel. Very slightly hollowed. This gave me a good target. I found the stroke where those lines started to recede a little from both the back of the bevel and the edge end of the bevel. After some trial and error, I fell into using two or 3 long drawstrokes to cover the entire length of the edge. As you can imagine, breaking an 8" edge into two or 3 pieces on a stone that is 1.5" is way over-square. I was sawing side-to-side more than forward. So this is what must have left the grooves on the stone, in hindsight. I managed to put a respectable, clean edge on the knife, though, in my own memory. I was happy with it.Anyhow, after seeing this, that idea to discover a better way to sharpen a longer knife on this stone got planted. What I had been doing to date was just the debur motion I used on the chef knife in my video. That had been almost immediately the first thing I fell into for sharpening, and I still use it for touchups and deburring. So I put on my thinking hat and came up with... circles. I never liked them. I still don't. I never used them. But that was the best idea I had come up with, and life went on.It was probably a year later when I randomly clicked into doing that rowing motion figure 8 when sharpening my kicthen knives, on that 6" stone I use there. And eventually I got around to remembering to try this technique on the pocket stone.I finally have the pocket stone and an 7" Santoku in the same room together. I got the rowing thing going on that little 1.5" stone, working my way up the blade on the one side. Then working my way back down the blade on the other side. It doesn't take very long for this to feel "right." And then I check the blade. I can feel pretty well when I have a razor edge, and this feels like a razor edge. But there's no bur. I do this another time, working my way up and then down. Still nothing. I try a third time, raising my angle just a hair, working my way up one side and down the other. Still nothing. I'm dumfounded, because I can feel I'm on the edge. I can feel the metal grinding off, and it's coarse but consistent; it's not a finishing stone, anymore, this way. And yet the edge has no fuzz. Then I finally look on the stone under a mag lamp, and there's these little balls of rolled up burr on the stone. It wouldn't have even occurred to me that I was capable of doing that, let alone on accident. I was peeling off that burr automatically while adapting this technique to this tiny stone for the first time and get getting used to the feeling.As seen in my video, I don't do anything special to debur a knife with this method. Just by finishing with single alternating strokes, you get clean edge with no microbeveling. I felt like this was the case, before. And I feel like the edge is consistently hard and durable this way. But I was never 100% sure if I wasn't just subconsciously raising my angle during deburring or not. This day convinced me I probably am not suffering confirmation bias. I just happened to hit the right pressure and to switch sides frequently enough when using this pocket stone that the burr was coming off as I wet. This also confirms this motion works for me pretty darn well.Also notice that it took me over a year to learn this motion, spontaneously. I hope this saves a step in someone else's timeline. But, OTOH, the time you took to read this far, you will never get back.;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

author: eKretz
author_rank: Frequent Contributor
timestamp: February 23, 2020, 06:52:14 pm
content: Ok. First of all, there are a lot of inaccuracies in the way you think you understand things working. The very first one I'm going to bring up is the hardness of the welding table. All welding tables are pretty soft. Most good ones that aren't homemade are actually cast iron. This because it's very stable and far less prone to warpage over time. One drawback is that you can't easily tack weld to a cast iron table. One plus is that you don't often need to anyway because they have holes for pushing pulling and clamping. This does take longer than a tack though.Next, the carbon percentage of "low-carbon" steels. These are generally accepted to be equal to or below 0.2% carbon content. So 1020 steel or below. They are effectively impossible to harden by heating and quenching unless they are case hardened. The average Rc hardness of steels in this category is probably closer to 10Rc.Next, the file not cutting over wide surface area comment. You compared this lack of cutting to the reason a fine-toothed saw blade won't cut once the chip clearance or "gullet" is clogged. Bad comparison. A file won't cut much at all in this situation because of the large amount of surface area in contact at once. For the file to cut you would need to apply a very large amount of force, but it would still cut at that point - until the chip clearance was taken up. A file's hardness is probably going to be in the mid to high 60's Rc. So only a very little harder than a good hard average knife blade. There are myriad differences between a file and sandpaper. A file also has a MUCH coarser set of teeth in most any case. So of course it will cut very rapidly in instances where surface area in contact is small. The harder the abrasive or cutting material, the less pressure it will take to cut for equal surface area in contact.I'm going to stop there for now. In future it would help if you constrained the length of your posts a bit. There is a lot to go through there. I have other things to do, lol.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 23, 2020, 07:07:35 pm
content: Just wanted to add also that if I had to cut through a 4" round with a 40 tooth blade I would definitely not do as you described, haha. I would simply remove teeth until only every other or every third were left. Then grind the gullets deeper.Regarding the convex stone removing burr/wire edge easier, this is because it is in contact with a low surface area and can CUT aggressively rather than rub or cut very little. Burr formation increases massively with pressure and the freer the cutting action the less burr is formed. The apex of a blade is on the order of tenths of a micron in width, so extremely flexible. If the cutting action isn't very free it will partially flex out of the way rather than cutting. Then you get a burr.The same can be done with a curved knife edge and a flat stone. If you have a straight edged blade then the convex stone will be of benefit in reducing burr formation but it will be difficult to keep the blade edge straight. A better approach might be to sharpen the blade with a flat hone and then do only burr removal with the convex hone.

author: KL27x
author_rank: Super Contributor
timestamp: February 23, 2020, 07:21:06 pm
content: QuoteI've done that, too, eKretz. But on a wood saw. So oddly, it is funny how I almost corrected you. For a wood saw, you have to leave every fourth tooth. But yeah, every third on the metal cutter.I'm too tired and way too busy to read the rest of your post, closely, my friend. The reason I posted this here, rather than in some kind of tool or knife related forum is because I know I'm going get stabbed by a lot of pitch forks. Over here, well, there's just the one still poking, and I'll get 'round to reading your latest issues later in the day.Thanks, in advance, and as always, for the friendly battle cry. See you on the field, soon.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 03:18:29 am
content: Ok eKretz, I sat down and read your posts. And...You know a lot more than me about rockwell scale hardness of stuff. I was just pulling numbers out my ass, to draw a picture. I stand corrected. I had no idea mild steel was in the 10's rc. Thanks.As for the rest, I gotta say. What happened? You're talking sense, now. Oddly, I haven't budged an inch, and you corrected me on everything, and yet we're in agreement. I agree with your last two posts, almost with everything.One thing I would nitpick about harder abrasive cutting with less pressure. I choose to think that the sharper and/or better geometry will cut with less pressure. E.g., tungsten carbide is harder than steel. But when we cut mild steel with carbide inserts, we have to take deeper cuts with a higher feedrate/pressure. This is because HSS inserts will take a finer and sharper edge. The carbide hogs off material faster, mainly due to tolerating higher temperatures, unless I am mistaken. So with the tungsten carbide, we can take deeper cuts at a time at higher tool temps.But let's get back. Now that you corrected me and I see the light, let's examine what we now agree on. By reducing the surface area of contact, we increase the cutting aggression and reduce the rubbing and friction. I agree. I inadvertently suggested that this increased the cutting to burnishing ratio. That is clearly not correct when we put that side by side to what you said. We go with your expertise. We increased the cutting aggression: rubbing/friction ratio. Much better, right? And thanks for making this so much clearer.That said, did you ever try anything like what I am doing? When you spent those years and several hours a week sharpening fancy stuff?All I'm wondering is... how did you use your stone? Did you buy a barracuda and then do like everyone else? Drag it around the dog park on a leash? Did you quickly determine that like everyone else currently says, that this barracuda dog sucks at running, jumping, and fetching, but what it really shines at is playing dead?I suspect that if you had considered all of these factors when you were using this stone, you might have tried some different things.If you understand what parameters and what feel and feedback you should be considering to get this tool to "chooch" at its best, in its stride, to do what it's good at... if you could find a way to let the tool do the cutting and not try to make it bark like the other dogs, then you might have gotten some different results. If you have one of these funny, scaly dogs, and you're not satisfied with his ability to catch a frisbee, maybe you could try signing him up for the swim team. He might surprise you.I'm still open to buying this fancy knife and trying it. And you don't have to answer. But in case you care... what about the Buck Vantage Pro S30V with the "Paul Bos heat treat?" This is running close to a hundo. But the spyercos are twice as much. So I hope you got nothing bad to say about this Buck or this heat treat. Even better if you can share a model you like. Heck, pretend you're buying a new knife. If you would like, I'll even send it to you when I'm done. I like to test it for at least several weeks, though. $100 soft cap? Maybe more if you twist my arm for something that strikes your fancy. That will be my payment to you. Because I'm not a knife guy. I'm in it for the process and the capabilities. And I have knives covered, already.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 05:55:39 am
content: I just remembered. I have a knife guy in my circle. So can reach out and see if he can be persuaded to buy a new knife with my wallet.My eyes are glazing over just thinking about shopping a knife.I'll hold off for tonight though. So if you want to be part of my experiment, speak now or it might be too late.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 24, 2020, 06:18:09 am
content: Quote from: KL27x on February 24, 2020, 03:18:29 amRight, better geometry does result in a freer cutting action also. My point was that for equal geometries, the harder material will cut freer. Again, many variables here.Tungsten carbide cuts much faster than steel cutting tools due to its ability to withstand high heat but also because it is much harder. Mid-70's Rc and higher depending on the sinter mix. Also the modern coatings are even harder and have more lubricity. HSS will not take a finer edge than the right grade of tungsten carbide - the caveat is that the tungsten carbide is much more brittle. Unless it's only used for very light cuts or in a softer material like aluminum it will crumble at the edge. For a very fine finish cut of very shallow depth it can be sharpened to a razor edge. Edge prep on general-use tungsten carbide is normally a very fine radius or chamfer - or both. Sometimes what is called a T-land, which is basically a very narrow 15° or thereabouts negative edge.Yes, increasing the cutting action is always a net positive unless you just want something to be shiny. I'm not sure what you're asking when you ask whether I have tried anything like what you're trying. I probably have though. I must have a couple hundred sharpening stones of all varieties, natural and synthetic, of all shapes and sizes. My general thoughts on sharpening are that what works for one purpose may not work for another. There is no one size fits all solution if looking for the optimal result. The process - and the tool as well if necessary - must be tailored to fit the task at hand. I've used Arks prepped anywhere from a 36 grit loose grit lapped surface to one that will reflect like a mirror. This is possible on very hard and tightly bound stones. Not so much with a synthetic hone that's designed to drop grit at the first sign of dulling.Buck's S30V has a very good reputation; from what I understand due at least in part to excellent heat treat protocol. If you really want a holy crap tough to sharpen steel - S30V is sort of middling difficult - try S90V, M390, ZDP-189, or something along those lines. S30V is just where it starts getting noticeably more difficult. It goes up from there. Along with the price. For a truly difficult to sharpen blade of S90V or similar you're probably going to be looking at $200 minimum. And really the hard part is removing bulk material to get the blade profiled the way you want it. Putting the finishing touches on at the end is the easy bit.Personally I prefer a full flat ground knife that is very thin behind the bevel. Most of my kitchen and pocket knives no longer have their original primary grinds - I prefer something flat ground to more like .010" behind the bevel. This not only lets them cut very freely but makes touch up sharpening take about a minute.T-15 HSS I have intimate personal experience with, as I made a razor out of it as an experiment after some guys were wondering if it could be done at one of the razor forums. It was crudely done one afternoon in my garage mostly freehand grinding with a bench grinder, but all the same. It is VERY difficult to cut. The bench grinder had a tough time.I've been through a lot of knives over the years. Many have been sold, traded or given away. Spyderco has good steel and heat treat. Some of their "Mule" test blades have been outstanding and very high hardness. Benchmade is pretty decent but doesn't range quite as hard in my experience. A "super" steel with a high hardness is a tough S.O.B. to abrade.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 08:39:06 am
content: Interesting.QuoteSpecifically, I was wondering if you have tried to increase the cutting aggression and reduce the rubbing and friction of the soft arkansas stone you used when you tried several times to sharpen supers steels, such as the S30V which you assured would skate right over like glass and that novaculite won't cut these steels full stop period?Or did you use a machinist square-verified flat piece of ark on it when it skated like glass?And I'm curious, because I got all kinds of blades to skate over arkansas stone like glass when I tried to follow the most common advice, and I have never had any of this super steel, yet. So I'm just curious, now. What is the myth or the fact or the stone or the technique.;;;;;;Hence why I said you assume or read or think this is not possible. Even if you have tried it, you may not know. Without applying what you know (and in this case you seem bent on saying what this entire thread is about is impractical, even though you haven't tried it), maybe you were using the stone "correctly" at that time. The correct way to use the stone, which is embedded in ages old internet culture going back and entire 30 years, is to make it the slickest block of glass you can and then to spend hours rubbing a straight razor you sharpened on an 8k waterstone to get that extra special something something on it which you can't describe but you will know when you feel it.Considering the stone has been used for many thousands of years, and during 99% of that many thousands of years, it was among the most prized of sharpening tools, I kinda doubt what you think is practical is actually the case if you asked throughout most of our human history.I respect this culture. These guys have a right to their belief system and hierarchy of knife steels and their own holy scriptures. I'm not going to go poke their nest or challenge their bullshit. But don't bring that stuff here to wave your dick. That you've BTDT and are a card carrying member of a cult which is obviously based on capitalism and trademarks than practical use and knowledge.After the 29 seconds of internet shopping, I already know what the deal is. When a special steel is only available in "high quality knives" for 200+ dollars, it's not a practical application of that material, but a trademark and an upsell. Somehow I never found the application where I am looking for a knife that is harder than w/e the heck mystery steel is in my knives. So using "modern knife steel" as a reason to ignore the whole point of this thread as impractical is a joke to begin with. Wait. Calling it "modern knife steel" is a joke to begin with. Modern knife steel is the same as it was 100 years ago. This other stuff is modern punch and die steel sold in knife shape to collectors.You can't even call it the modern knife steel if 0.01% of knife work is done with it. If it was "modern knife steel" it would also be sold in a basic shape on a basic stick handle for the guy that does that job where it is so superior.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 24, 2020, 04:10:35 pm
content: Now hold on, you seem to be reading different things than what I wrote. I said the Arks (or any silica based abrasive stone) won't cut thecarbidesfull stop, period. Theywillcut the steel at the coarse end of the spectrum (Washita, Soft Ark), but extremely inefficiently. And they do it by cutting the matrix around the carbides and dragging them out whole, sort of like yanking the gravel aggregate out of concrete.And yes as I mentioned I have tried Arks and many other stones on the "super" steels very often - with a very coarse and free cutting surface. They still will not cut the carbides. They will remove steel, albeit very slowly and dragging out the carbides by digging around them. They also give up quite a lot of abrasive during the process, which they really don't do with plain carbon steels.The only reason to use a super smoothed stone surface is for something like shaving, where feel on the face is important. An extremely fine edge with as little tooth as possible is the goal. This is the kind of edge you want for a "push" cut with no lateral sliding (or sawing, if you will) motion involved. For a sawing type cut you want some tooth to remain and a coarser finish works better, as well as keeps cutting longer.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 04:14:28 pm
content: I'm sorry for my irritation to spill.You can take over this thread with your own special interest. I'm not interested in boutique knife steel circle jerk. I've read everything you said, like you're repeating it straight from this circlejerk.Apologies. I think I'm done. I'm way better with people before I open my mouth.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 24, 2020, 04:17:23 pm
content: Quote from: KL27x on February 24, 2020, 04:14:28 pmYou seem to have a social issue that I don't understand. As far as I can tell I was only answering the questions that you asked. I guess I will refrain from participating in your threads from here on out. For anyone else reading, I'm not repeating anything from anyone, only relating practical personal experience. Attached are several of my own micrographs of a blade that has had carbides yanked out of the surface, both at the coarse level and fine. In more than one, you can see the carbides jutting out that are not being efficiently cut. At the coarser end the tiny black dots in the image are cavities that used to contain carbides. Judge for yourselves. Images show approximately 1mm width.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 04:40:17 pm
content: Yes I do and I'm aware of it. And I apologize again. More sincerely.So let's just be clear.The video I made and the thread I started about convexing an arkansas stone is impractical in your opinion to the point of immediate dismissal because of1. "modern knife steels"2. Some blades have to be flat1. These modern knife steels are so useful they are only in collector knives. A guy who needs a knife for a task doesn't like a knife that grows legs everytime he set is down in a working environment. He wants the tool that does the job, not a walking billboard that says "resale value for crack." Where's the S30V box cutter? M390 exacto? No? Apparently these steels are super for making feathersticks and stabbing trees. I'm hesistant to even call this a knife steel when it's only available in a general purpose tactical folder kinda deal. It it's what can be considered "modern knife steel" it should be in working knives for industrial and professional use. Where the super steel carpet knife, exacto knife, carving knife? Let alone a simple chisel? Why they only come in tactical chest piercers/box cutters? Tools which require a very keen edge are not going to benefit from these. This is where the ark stone can be most practical usage of. To maintain keen edges. Sharpening is part of the usage of these tools.I'm not disparaging your choice and use of your own knives. I'm sure you get a lot of value, along with the other percentage of guys buying these for other than collector item. But lets stick with the majority. 99% of people who occasional need to use sharp edges.2. Some blades have to be flat: So far in my life and this thread I have identified 2 of these. Jointer hand plane. I wonder how many people own use one of those, today. And the other? Jointer planar knives. These are the blades in a jointer and are can be 12+" long. I suppose these must be sharpenable only on a flat stone that is wider than a foot? When I saw Matthias do exactly this, I cringed inside. To dig up and drag around a 200 lb block of stone to sharpen a 40 gram planar knife. I imagine I would just sharpen it with Tautech's granddaddy's scythe stone and a straight edge.So I'm going to ignore these for now.Before you get worked up. Consider the history of man and think what you know about this "cutting aggression" and surface area thing. Do you think man has and will always use ark stones flat, as polisher/finisher/microbevelling stones? What would they have used to sharpen their knives in the first place, then?If they used rounded river rocks that were faster and better at sharpening than a rounded novaculite stone, then these magic river rocks would have been the valuable item.You say you've tried this stone burnished smooth. Freshly lapped with 36 grit carbide. Try using it so it works the way it is, indefinitely, through use. This is where shines. My stones don't have a finish I refresh. The finish is in a steady state of continual use. Only if you try to use it like this can you experience the practicality of the entire system. What is advocated by the largest voices today, makes it impractical to the point of some esoteric hobby slash achievement badge.When I say this is practical, it's because I have done it for 2 years, now. There's pretty much no way to maintain a razor edge on knives and tools faster or more conveniently, when you consider the entire process, IMO, footprint, cleanup, maintenance. I think this might have been why these stones were valuable. Not for what we use them, today. Because this stone is unlike all other synthetic stones made today, but we try to use it the same way as all these others.Even the sellers of these stone demonstrate this nonsense. Why would they do that? Well, smiths might get half their gross from these stones, but I bet it's 1/10th their net. That ensures people buy it, throw in in the bottom of a drawer never to be seen again, then buy some other crap. Repeat ad infinitum.This stone might be more than it appears, if you are interested in a practical tool that is exceptional for what it is REALLY good at. You can glaze any hard wearing stone and make it play dead. Jade, granite, w/e stone you pull out of the river, probably.A 2x4" isn't harder than aluminum oxide. But if you hold a 6" length of this flat against your belt sander, it will stop cutting once the high spots are removed, and it will start rubbing. You can stall your beltsander. Or you can continue to turn electricity into heat as long as you like. If you understand that even a tiny looking bevel on a hard steel is like a 2x4" against a belt sander, then you might start to get the picture I'm drawing. OTOH, if you take that flatened hunk of 2x4" and draw it over the round part of the belts sander, you're cutting again.As I said once to Coppercone2 in an aluminum cube flattening project, if you wanna do it efficiently, you make it flat enough first using direct abrasion. Then you polish. You don't try to keep polishing/lapping until the cube is flat.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 24, 2020, 07:19:27 pm
content: Quote from: KL27x on February 24, 2020, 04:40:17 pmWell, I appreciate the apology, so let's maybe just try to keep the tone more civil and we can continue the discussion. I am not being intentionally dismissive of convexed hones, just don't find much application for them personally except in certain cases.Now, I've already mentioned that stones need to be used (prepped or not) differently for different purposes multiple times... You seem to want to gloss right over this. If you want to use your stone the way you're using it and it's working well for your purposes, more power to you. There's nothing wrong with that and I never said there was. That is how it should be.Ages ago, sandstone would have been the stone of choice for coarse sharpening. Arkansas stones and their ilk (coticule, Thuringian etc.) were highly valued for their finish sharpening ability. Coarse stones like Washita and Turkish emery stones were very highly valued for quick sharpening. Until synthetics came along. Now natural stones are mostly a specialty item for people like me or you.Next. I am not a proponent of the "super" steels and have not once said anything to that effect. My sole commentary about them has been that they're a bear to sharpen effectively with anything short of superabrasives. Again you are reading things into what I've typed that just don't exist.Regarding your final paragraph: I can not shave my facecomfortablywith an edge that has been finished with a Soft Ark. If you can do that, you are doing something that pretty much no one else I know has been able to accomplish. Good for you.Your "idea" of using the stone in its natural state is not new or revolutionary. You've been doing this for two years - I've got some I haven't resurfaced in 30. I too am a proponent of doing that... Once the stone is flat and has settled into a state where it is smooth enough for the task at hand. Surfacing the stone to a high (enough) level is exactly the same thing as long as it isn't taken to too high a level. It's just accelerating the wear so the stone gets there faster and is uniform across the entire surface... Not sure why you seem to have a problem with that.Will I be in a great hurry to convex all my stones? No. I prefer to have a curved blade and a flat stone for razor hones. This keeps things repeatable as I progress through the grit levels from one stone to the next - this is important when the blade is guided by two point contact at spine and edge so that contact is made all the way to the apex right away in every step of the process. For the final finishing stone a convexed stone might be fine but I don't see the need, and getting a repeatable convex surface would be a total pain. It's very easy to check for flat repeatably...I am a machinist. Repeatable is sort of our thing.For knives I really don't much care what the hone shape is, as I sharpen freehand and stone shape is mostly inconsequential if the knife blade isn't dead flat or recurved. In those cases I would find a convexed stone quite useful.As far as flat knives or blades go - they may not be plentiful in your daily life but they are very plentiful in industries that shear paper, cloth and plenty of other materials. I'd also challenge you to find a curved sear in a pistol or rifle trigger - good luck. You aren't considering all the other things that other people might use a stone or hone to do, only your own application.Ah, and almost forgot about the foot long blade you mentioned. Very simple, these types of blade are most efficiently sharpened on a machine tool. A surface grinder that has a table which travels in as near as possible a perfectly straight line. As fine a wheel as desired can be used, and final touch up can be done by hand if necessary.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 07:39:06 pm
content: Thanks for putting up with me. Truly I appreciate everybody on the forum, esp the guys I argue with the most.It's way better for me to be an idiot here and to butt heads with people that know I'm slightly off, than to go try to find new people to upset.And I'm sorry when I get abusive. I have huge personality problem, and I'm aware of it. That doesn't mean I can always control it.QuoteI can't either. I can do it a couple times, but by day 3 or 4 or so, my face will call in sick. The hairs will still be jumping off, but skin is getting overexfoliated in the process. The way I look at it and do it:1. I grind a new apex with the soft ark, which makes a sharp and hard edge. This takes less than a minute from the time I first put the blade on the stone. This is what makes the good edge, period.2. Polish the high spots off the bevel with the finish stone. Which I like the ruby. Just me. The sharpening stone will be plowing or furoughing the bevel. This leaves fluff on the bevel. Just like you might take your flat machine shop india and run it over a flat honed surface just to shave off burrs and high spots. That's all I want to do, here. To smooth any high spots down on the bevel. This makes the bevel feel smooth. And it improves the corrosion resistance, so water doesn't stick into these grooves. I am not trying to completely remove the scratches, at all, personally. So this polish stage is even shorter than the sharpening. The way I do it, this isn't really affecting the edge, hardly at all. But that said, ruby is a good cutter and esp when slightly rounded, of course. So this removes visible metal. I still think it will overburnish and weaken the edge if you do this too much. I'm not trying to improve the edge, here. This can make it smoother. But it can only make the edge worse, in terms of durability.3. Strop. 3-4 swipes on the leather. The strop is what smooths my razor's edge. Way more efficient IMO then trying to polish the bevel all the way to the edge. (I don't see how the edge can stay hard that way on a hard stone like these, unless you add some lapping paste or grit. This is like holding that 2x4" against your belt sander and waiting until you take off some actual material. That doesn't make sense unless you add some lapping compound/paste.)This is about once a month, maybe. And from watching how other people put an ark, even a soft, into their razor sharpening routine... what I just described is completely alien. If I had to do what they do, I would be back to Bic/Gillette in a heartbeat.I'm sorry if you feel less of my knowledge about sharpening after reading this. But it works.My brother asks, so when start to get dull, I take the razor back to the ruby? My answer was NOO! When you don't get a good shave, start back with material removal, not polish/burnish. You might get it to cut ok with just the ruby, but it won't last very long. Waste of time.So it's not that the soft ark is lightning faster than anything else. The reason it's efficient in my applications is because it's fast enough, and it leaves very little else left to do to the edge. The way it removes the material leaves the razor edge right there. It removes material accurately without overburnishing. Or vs a lapping stone, without that bit of roundover or whatchacallit. There's a bit of snipe when you lap, dependent on the particle size. Lapping stones won't overburnish.You have to pay attention to how much area you have on there with the hard stones that don't slurry. If that area is too big, you will take down the high spots, then start to burnish (and to dull stone). The soft ark (when convexed) is your sanding belt that can just get all the way through this entire 2x4 (common bevel size and hardness for my tools) and keep chugging. So it will leave about the best edge while being able to actually sharpen effectively. The finer/finish hard stones like the ceramics and translucent ark are gonna stall and burnish. Just get the high spots off and quit before you get diminishing returns. Burnishing will fill in scratches with burnished metal and refine the surface, but it is changing the structure of the underlying metal, weakening it. This doesn't matter for a mirror, but it has an effect at the apex of your edge.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 10:37:36 pm
content: QuoteWhat people won't or refuse to understand is that this ark is sharpening fully the entire bevel, not finishing. What I'm doing is not following the bevel that was set on another stone, and occasionally hitting the apex and the back or what. This is cutting the entire bevel back. The edge (V or flat) bevel on these knives is completely formed by this stone and these movements. AND leaving the razor edge. This is the right belt to use for this, more or less. Other than for major chip out or something, this is the only stone needed to sharpen until you need a major regrind/reprofile because the edge bevel is getting too wide.You cannot "finish" on this. Because you're removing the surface and putting a new one on as you use this. This is a sharpening stone. People who use flat ark stones might not be able to get that. Because that's not what they know about the stone.And I can do major work the same way with the coarser india. Major like making knives from nothing.These are the most consistent bevels on knives and the first time I consistently have symmetrical tips on my knives. The repeatability is unexplainably consistent, despite looking like all human talent or control. The motion goes on autopilot and you just ride it like a bike, you're aware of your spot, and you're holding it. Did a sharpening on one other new knife, from a coworker, a cheap winchester knife. Anyhow, used the coarse india, whip whip whip whip, and could easily stay on the factory bevel. On my knives I wouldn't care, so that was a cool test to get to have.I'm not bragging. I'm agreeing these are legit concerns that ordinary people have. I just didn't let that stop me from trying.If you listen to the sound in the video, you might put it together. To hear the sound that coarse and to get the shaving edge, you have to stay on the entire bevel.QuoteIt seems against the norm of the ideas how to use soft arkansas stones. But this might just be the last few decades of internet. Seems like most people "recondition" to keep their stones cutting, because they are glazing them through use. I don't think this is new, either. I believe this is the way they were used for most of history. This flattening craze is perhaps spilled over from the synthetic industry and misapplied. If you believe the American internet between 2000 and 2017, there was no such thing as a convexed stone. Stones were either dished or flat. I was there and I looked. This is what our gen knows. I remember in the 90's a text webpage describing this way to use the soft arkansas. I never did it until 30 years later, though.This is one thing you conceeded me that you admit is impressive. That I can shave right off this stone. This isn't a parlor finishing trick to massage the apex or anything. This edge is just a byproduct of the sharpening.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2020, 11:36:57 pm
content: do you have any microscope pictures?

author: eKretz
author_rank: Frequent Contributor
timestamp: February 24, 2020, 11:40:16 pm
content: Same for me. I can shave with the edge from a Soft Ark or even a Washita one time, but not repeatedly. I like the edge from a Spyderco Ultra Fine pretty well, which is similar to your ruby hone. Your sharpening process is pretty much the same thing I do... Coarse stone sets the edge, finer stones just smooth the remaining high spots away. Plain leather strop for the finish.I've tried all the alternatives and every one can produce a good shaving edge but they all have their own little intricacies. I like the edges from Japanese natural stones a lot, but they are awfully expensive. As I enjoy the process and just sharpening in general I have probably spent a lot of money that to most would seem excessive and totally unnecessary. That can be said for any hobby though.

author: KL27x
author_rank: Super Contributor
timestamp: February 24, 2020, 11:54:46 pm
content: Copper, for you, anything. I will try tonight. Right now I have to put some orders in with Mouser and get some adhesive added to a PCB order.

author: coppercone2
author_rank: Super Contributor
timestamp: February 24, 2020, 11:59:12 pm
content: i managed to spark a 50$ knife (SOG trident) and this might fix it (battery)

author: tautech
author_rank: Super Contributor
timestamp: February 25, 2020, 12:08:28 am
content: Great discussion guys, enjoying every word !As it progresses I'm understanding where KL27x is coming from better and better but that's not to say I agree with it 100%. It's his style of sharpening, that I fully understand but not mine......but I'm not sharpening face scrapers !A single combo wet stone does 99% of what I do and another 4 or 5 stones just sit on the shelf unused.A circular motion using the entire face of the stone has kept mine quite flat (but not perfect) over several decades.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 25, 2020, 01:59:42 am
content: Yeah for most general knife sharpening most everything I've got is overkill. I could easily make do with a stone or three but then I wouldn't have quite as much fun!

author: KL27x
author_rank: Super Contributor
timestamp: February 26, 2020, 06:47:10 pm
content: Chef's knife. Used only lightly since the last video.My straight razor. Best I can guess, my last sharpening was around a month ago, and it has essentially been used every day since. I have done nothing to it, since. Not a single swipe on a strop other than immediately following the last sharpening.Curiously similar to the unfinished chef knife to the eye. I finish for the feel, and my skin can't tell the difference between this and a bevel that is shiny. This ruby will make a really shiny mirror, if you want that.This is the first time I have looked at an edge under the microscope. Not my bag. I'm impressed with myself that this looks exactly like what I described. Just knocking off the high spots. You can even see the difference, really. You can feel it.This is a knife I ground myself, pretty close enough. It was a mora lainated blade, with a scandi grind. I chopped about an inch off the tip and obviously descandied it. eKtretz, I originally left the tip really fat, because at the time I couldn't form a good tip. I figured I would get back to it when I got better at that. After some time using these convex stones, i took this knife and finished it with the curved Norton. This is when I realized the amount of force and resistance when reprofiling on the Norton is too high to use like my razor stone; hence, i added that additional block to give it a more positive grip, and to keep the blade farther from myself when using this higher force. But otherwise, this is the best tip I ever made, anyway. And unlike trying to do it on a flat stone, where you constantly adjust your angles and squirm this way and that to get what you want? This is almost completely autopilot. The stone is the compliment of natural biomechanics, making it an ideal and infinitely adjustable tool for making various lengths and curvatures of clam-shell shapes; e.g. knife and edge shapes. Just there's no instruction manual that would make sense for it. If you wanted to learn it, you are just as well to watch someone else do it, then get on the bike and start pedaling.Some hard evidence that perhaps I'm not prone to blowing smoke or having flights of fancy. I made two of them; this one is still unused. The other is on the saw, and has been my do-all for the last couple three years. I also increased the set of the teeth using only smooth jaw needle nose pliers. She's right as rain.edit1: Fudge. I am gonna edit this to make the pics smaller. I forgot how to do this.edit2: Ok, everything I do seems to just make it worse. So this is it.edit3: I already knew this before looking under the microscope. That the bevel on the chef knife is going to be more-or-less flat but actually slightly convexed. And fairly consistently so. Everything you do on this convex stone, when using the motions I use, produces varying degrees of this slight convexity. This is not necessarily a bad thing for these tools. It is generally advantageous for sharpening. This is one of the other ways to increase the cutting and reducing the burnishing by reducing the amount of surface area on the stone while cutting in the edge. And it produces the tip very easily. You adjust your motions and the spot on the stone you are using, and this adjusts the amount of convexity you get. This is what makes it so easy to blend in the tip. I did not use a slush/lapping stone to blend things in at the end, on that tip; just a quick rub with wet/dry; you're looking at the grind right off the norton.It's like flying a helicopter. It's hard at first, because there are so many variables you are learning, but then things settle down. Unlike a helicopter, you get to crash as many times as you want without any significant repercussions. Once you can keep in the air without thinking about it, now you can make your flight plan and stick to it. And when sharpening, you have built in GPS. You know when you're on the bevel, proper, because you can feel the tool is doing the work. I'd go so far as to say, as long as the file is chooching rather than choking, and your angle isn't higher than you like, you will end up with a razor sharp hard edge where bur falls off with mean look.Even the edge will tend towards a slight smile/curve. You can adjust this to a lot (the gouge chisel) or a little, in order to approach flat. Flat is relative, somewhat. Just a matter of increasing the radius until it's flat enough. And a matter of controlling this motion, now that you learned to fly this helicopter. OF course on longer blades, you adjust the shape of your edge by where you spend more time. It's short blades (chisels, I guess) where perfectly straight is not going to be convenient to maintain.eKretz, btw. When you mentioned the "high pressure" thing, I sense you watched a Stefan Wolf video. Yes, that works. But it's not overcoming the surface area and getting the stone to cut like a file. The file is still choking. This force causes the stone to crumble and release particles. Then you use this flat ark like a lapping stone. And notice how long this takes on a reported soft knife. And then there's that "microbevel" to get the schmoo off. It's a perfectly good way to use the stone, if that's your preferred paradigm. I have tried it, and... meh. Sub par. Also, the particles are of dubious efficacy, IMO. I've tried using ark dust as a stropping compound, and my conclusion is it simply doesn't cut effectively, even carbon steel. So this method just might be more of a rough/live file action as much as lapping.You can get the stone to chooch without curving it, too, just by tilting the blade just slightly towards the edge and drawing the blade. But this is going to quickly turn the stone into a saddle if it becomes your norm. This reverse curve hugs your bevel and increases the surface area. Then you have to fix it. Reflatten it? Or... just take the corners off and keep on chugging? Maybe your decision is different, now that you read this and will have tried it by then.So thanks to all participants in the thread. This forum is a unique place where new ideas sometimes get to see a glimpse of daylight. When it come to these file-stones, keep your barracuda in the water. Shape first, shine little. Burr is a four letter word. Burnishing should be. Shiny != sharp. And also, don't believe for a second that all of our ancestors were nearly as stupid as we are today. And if you think knowledge can't be lost now that we have the internet? It's the exact opposite. History can be rewritten easier than ever.In case anyone would like to know as much about machining as I pretend to, it's free and easy. Just watch ToT videos for an hour a day until you're caught up. Don't overdo it though. If you watch watch more than 2 hours in a row, you might have an existential crisis. Behind that carefree veneer and the dad jokes, Tony is a deeply troubled man.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 27, 2020, 04:55:58 am
content: Sorry, not familiar with Steven Wolf? Was it? I don't watch too many sharpening videos... Usually only a few of the ones someone posts in a thread and calls attention to. I don't watch a whole lot of YouTube at all really. I do like OxTools? I think it is - for machining videos though. Most of the stuff he does is done the way I'd do it.

author: KL27x
author_rank: Super Contributor
timestamp: February 27, 2020, 03:33:13 pm
content: Nice. I think I'm going to like OxTools.Not Steven. Stefan. It's kinda catchy name because it rhymes with Steppenwolf.There's not a lot to see there. I have watched it because... I have searched every bit of knowledge about using oil stones and arkansas stones on the internet for a long time, now, trying to figure out where this curved/convexed concept went. Stefans videos are mostly just demonstrating sharpening kitchen knives on mostly synthetic stones which he likes to keep super flat by lapping on plate glass. So yeah, that's a niche thing for sure.I remember maybe 5 or 6 years ago, when I came across a Paul Seller's blog post where he complained about the modern schools of thought on this. "In the old days, no one flattened their stones." I thought here was the master. He was there. He knows the score. Then he goes on to describe DISHED stones working fine. I have to admit the norton india (what he was describing) is such a good cutter, it probably doesn't matter how you use it, as long as you end up with the angle you want. But man, that was a disappointment. I thought I found the holy grail after 20+ years since reading that text description on the web in the 90's which described many of the benefits and reasonings behind this curve, although at the time I didn't understand all the lingo and had some internal conflicts.And I just don't think our ancestors didn't know how to use a file. Yet, today, check our expert knowledge. That link Gregg put in the second post of the thread. "We really have no clue what the burr is when it comes to grinding." What? It's pretty darn crystal to me.QuoteThis is fine, but it was of no use to the worker sharpening his froe, between say 500-1800's. Do you suppose he used a flat natural rock or a convexed one? (Or a dished one?) I think through a lot of this time span, they actually probably used hardened steel files for sharpening more than anything else. And we can make a new analogy. Do you suppose anyone tried making a foot wide sharpening file for this job? Perhaps. But eventually this guy figured out how files work.Today, we know only what the advertisers/marketing dollars want us to know. Our internet knowledge is a regression to a mean in many ways. The louder voice is the truth. Our knowledge is fluid; you could say our knowledge is cultural. And today, our cultural knowledge base is highly influenced by marketing.All of the imagined downsides of convexing this natural stone... this I will say you might be mistaken, until you have tried it. But take the crock sticks in a wood block method of sharpening. This is highly recommended and lots of folks like it. How do they sharpen their chisels and their perfectly straight jointer plane blade using crock sticks? What objections real or imagined about the what I have shown does not ACTUALLY apply to this crock stick thing? But if you suggest this crockstick, you'd get patted on the back. Good boy. If you suggest something way better and more versatile, you will be shot down in the face.According to Jarrod, this method of using these stones was at one time a highly guarded secret. Today, you could shout it from a mountain, and it wouldn't matter. Heck, I read about it, and I still used this stone flat, only. Eventually when I dug it back out of the darkness and decided to make it work, I did it by favoring pressure by the edge to make them sharpen. After some trial, I liked the feel and the edges. Then they dished, then I flattened them out and started over, for I dunno... a year or 2 before I just got tired of it and decided I'm going to go full vex. That's when I googled and found Jarrod's video. First time I saw anything about this since the 90's. Two years of using them like this and now I feel... there's almost no downside and huge, huge upside. I don't want to oversell it, but it's very practical.I keep a couple of flat stones for deburring flat surfaces and as flatness-checkers, to find the high spots on a piece of steel. I would never sharpen anything on these, anyway. So I dunno what the flat arkansas as sharpening stone is even good for.I haven't missed it. Yet. Small bits can be useful for filing and as laps used with paste. But a large flat area of novaculite is not on my top 10 ten useful tools list.

author: eKretz
author_rank: Frequent Contributor
timestamp: February 28, 2020, 03:40:32 pm
content: Well, to put it simply the surface grinder would be of no use at all to the guys using hoes and what have you. It's totally inconsequential whether they had a perfectly straight edge or not.Regarding the use of a flat stone, it's really no different than the use of the convexed stone when you're working on a blade with a convex curve. The blade still only makes point contact with the blade whether the stone is flat or convexed. If the blade is perfectly straight then the convex stone would offer some benefits, but also drawbacks - keeping the blade straight over time being the most significant. If that doesn't matter then there are no major drawbacks that aren't also present on the flat stone.Convexed stones have never been any kind of secret, they've been used by tradesmen for centuries. People using scythes especially. They just may not be common knowledge to the common man - but that could be said about ALL sorts of things.

author: KL27x
author_rank: Super Contributor
timestamp: February 28, 2020, 05:46:32 pm
content: Quote from: eKretz on February 28, 2020, 03:40:32 pmIf you are looking just as how it cuts the steel, you are probably right.QuoteYes, you recognize one major disadvantage of the flat stone in on this outwardly curved knife. There are more.Wear pattern is the most significant other problem, IMO. When you sharpen this curved knife on the flat surface, what is going to happen to the surface of the stone, and how is it going to wear? You think you can keep the entire surface relatively flat and even? This is all the while you have to negotiate the curve of the knife, manually, while drawing it over this vast featureless area while playing keep-away-from-edge/corners? When sharpening knives, the only place you can reach the part of the edge by the handle on some knives/tools is at the edge of the stone. Are you going to compensate for that, too?In a convexed stone, it's left to you to use and wear down the 10% extra-curved high spots (which cut better and wear faster) which develop, to keep the stone in a useful, uniform shape devoid of weird spots. In the flat stone, you are trying to wear down the 90% of the stone that is flat, in order to reach the same level as the 10% that is dished. That's a fool's errand. By the time you get close, you accidentally made a new lower low spot. You're chasing your tail the whole time and losing that battle.Now the ones who can "actually" sharpen on this flat stone, they (nearly universally) do this by favoring pressure over just the edge of the stone, whether consciously or not, and drawing the blade over this line/area of the stone; and thus they keep the file cutting rather than gliding/burnishing. The wear pattern is just as bad, saddling the stone on the edge(s), end-to-end, because you can't practically use the whole edge all the way to the corners. I notice people on YT who use this method; at least when they are actually sharpening, not just polishing/finishing with this stone. Jef Jewell, for instance, he took the video down, but he had one where he flattened his Spyderco fine bench stone. He dished his spyderco, just like what I described, like a saddle. A superfine, sintered aluminum oxide stone. (And no, he never got that thing flat, again. At least not by the end of his video and what IIRC was over 4 hours of slave labor by his description). Imagine how much faster than happens on a piece of soft arkansas when it's actually filing, not skating/burnishing! These guys who sharpen on this soft ark like this, they frequently re-flatten these stones as part of maintenance. The stone stops working, and they might think it's because it's not flat. It's because it IS dished. And there's nothing they do (in their videos) which requires that stone to be flat in the first place, IMO.QuoteThe folks that used these "scythe" stones sharpened all kinds of things on them. "Scythe stone" was just a name, but we take it literally. I am guessing it is probably only in the last 100ish years we have relegated this convexed stone into this niche box for recurved edges, specifically. In fact, many a time I see people complaining about curved stones. The idea is so repulsive to them, they will argue that a narrow width stone, kept and maintained flat to be sure, will do "exactly the same thing" for these recurved blades and scythes.Curiously, even when you buy a scythe stone, say from Baronyx Co, it comes with two flats, say the top and bottom. And the sides have some curve but only in one axis. The way you hold and use this stone, whenever you put a recurved edge on it, out-the-box, it will contact only on either/both edge(s) of that surface of the stone, until the edges of that stone wear down and the surface starts to convex.We like flat stones. We like curved stones for recurves. We like rods for either, though? It's nothing more than cultural. We like perfection, and a flat ark stone is perfect. At being a rectangle. OTOH, if you learn and appreciate the difference between direct abrasion/filing and lapping, you might see how pointless that really is, in practice, to have a flat soft ark stone. Or maybe not.Personally, I have as much use for a flat soft ark as I do a flat file with the same tooth geometry as my mill file but the size of a football field.Additional shower thought #1:I can imagine 1 good sharpening use of a flat ark. It would be good for a straight but interrupted edge. Teeth. You could, say, "sharpen" a saw blade by abrading the sides of the teeth to an edge, again, albeit with zero clearance. That kind of situation. Or for sharpening the flat side of the tips on a serrated blade. The convexed ark might round these things over just that little hair, reducing the clearance in the case of the saw. But maybe my imagination is lacking on other sharpening uses.Shower thought #2:The mill file the size of a landing strip would be useful for the same things as the flat ark is, just bigger. Adding straight and planar chamfers/bevels to long pieces of steel. Just breaking the edge super accurately. It would be better at keeping this "microbevel" in a straight line, in case your straightness matters to that degree. You ought to be handling this 99% in the bevel stage, though. And it would be good for making larger areas of steel shiny, by burnishing. And it would be useful for filing interrupted surfaces with adequate swarf clearance.Even in diamond files at the fine high grits, I use a tiny file 30x for every time I use a large plate. And diamond is the only good way to cut tungsten carbide. And diamond files are way more open-pore (way larger gullets... more like a rasp) than ark stone. Thus they will cut a much larger area, relative to novaculite. There's also the bit where burnishing an apex into mashed potatoes isn't really a thing for tungsten carbide, to my knowledge.

author: KL27x
author_rank: Super Contributor
timestamp: March 02, 2020, 04:53:00 am
content: http://journals.ed.ac.uk/lithicstudies/article/view/1672/2316Roman Quarries found in northern Germania.QuoteNote "elliptic," not just rod-shapes.A Dictionary of Greek and Roman Antiquities. Edited by William Smith and Charles Anthon.(I'm writing it almost directly verbatim from my phone... dunno how to get the entire url to my computer, I guess I could email it, but that would be a lot of annoying tippy-tapping with my fat finger).Quote;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;This doesn't prove the Romans (or are these guys the Greeks? I think Pliny was a Greek) used elliptically cross-sectioned and/or rod-shaped novaculite for sharpening their blades. But if you tried it, you might be convinced for yourself.And if you have ever tried to convex the surface of a mud/lap synthetic stone, you would also be darn sure for yourself that these romans weren't making elliptical and rod-shaped pieces of softer-bonded sandstone for sharpening.They probably also made some flat sharpening stones out of the novaculite, too. They were probably used for very small instruments. E.g., a flat piece of soft arkansas works fine for sharpening very small chisels and exactos knives, in my experience.;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;Now, if you can believe modern accounts, these Armenian and Cyprian stones would have been a distant second to the Arkansas stone. And these ancients would have probably loved and been right at home with the Norton India, having had documented experience and perhaps an established preference ("confounded as diamonds") for these denser kinds of stones for their whetstones.;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;This cultural preference also affects our knife profiles. Today, if our knives come from the factory with an accidental teeny bit of recurve near the guard (sometimes this is due to human input on the grinding wheel), most of us have to "fix it." And many of our knives comes with "sharpening notches" ground out of the blade next to the guard; and/or many people add them. Or we use the Japanese style kitchen knives with no guard at the base... just razor all the way. If you look at older western knives, they hardly ever had these kinds of features. Even the ones without a full bolster/guard often had an area of unsharpened blade at the base, though the name of this eludes me, ATM. And the well-used examples, sharpened many times, they developed a bit of a "boning knife" recurve next to the handle/guard. These old guys had no problem sharpening these knives. There was no special attention to this recurved area. No need to whip out a special stone or technique. It was not an issue; no extra effort or time; no string or tendons or fibers getting caught in a useless notch. My modern Case pocket knife came from the factory with a little bit of this "boning knife" grind at the guard, out the box. Case is still keeping it old school.Perhaps one day, 100 years in the future, our descendants will find these sharpening notches to be a dead ringer that the knife dates to those years when humans became so advanced, and we became so connected and efficient in our ability to share and spread cultural knowledge, that we actually forgot how to sharpen a knife.