wrong carbide burr used? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: July 28, 2020, 11:36:30 pm
content: if you use a carbide burr on aluminum, in a die grinder, which is says not to, is this because clogging issues, or does it actually damage the edge?I was using one for a while with cutting oil (basically spraying it down frequently) to clean up some welds. One of the burrs got clogged and I soaked it in sodium hydroxide to clean it up. (got lazy, thought alumitap would work because.. its carbide. and alumitap is for cutting aluminum.. the milling machine does not seem to have restrictions for using carbide on aluminum really, at least the proxxon ones). And the dremel has a carbide burr that I think said nothing about not using it on aluminum. Anyway FYI alumitap sucks and 'light lubricant' seems to be the best for misusing burs (I used the 'precision' electrical lubricant because I happened to run out of wd40).I ordered proper aluminum burrs, but are the ones I used still fine? I am basically learning how to use them good, and I did not really cut steel with them.. and I don't want to learn on broken tools. If they are considered fucked up I don't want to struggle with them, and in general using burrs is a bit of a pain in the ass. I don't have a good feel for what 'worn' is.It says not compatible in the radnor catalog. I assume its just because of the clogging issue ? I was actually using stainless steel flap wheels on aluminum too, and I noticed they actually sell aluminum flap disks, so I got those and a aluminum grinding wheel.FYI : I used 2 carbide and 1x old tool steel 1/4 inch burs to cut Al gas welds (excessivematerial added).

author: jpanhalt
author_rank: Super Contributor
timestamp: July 29, 2020, 12:19:04 am
content: Aluminum alloys vary from dead soft (1000 series) to some very hard and difficult to machine versions (7000 series). I have no experience with the 8000 series and relatively little with the 7000 series.The dead soft 1000 alloys are in my opinion about the most difficult to machine. I tend to treat them as if hard lead. They can be work hardened a little. 3000 series (sometimes called half hard) are similar to the other grades but softer.Most of my experience is with 2000, 5000 and 6000 series. For those, I use ordinary HSS or carbide tooling. If milling, I use 2-flute instead of 4-flute cutters for better clearance of chips. For good filing, you may find coarse and coarse with serrated edges best, e.g., Vixon files (https://www.amazon.com/Aircraft-Tool-Supply-Nicholson-Vixen/dp/B005VR56SI). They will turn a chip almost as nicely as a lathe.Burrs of HSS and carbide work (there are different carbide grades for aluminum and steel). You will want a coarser burr, probably.

author: coppercone2
author_rank: Super Contributor
timestamp: July 29, 2020, 12:24:48 am
content: other then gumming, the edge is not some how destroyed by the gummyness ?I already use a aluminum file, but the flap wheels and specific burr is new to me. The aluminum file can be cleaned with a stainless steel brush nicely. I use a big square brush (I think from the paint department). Nichelson sells an aluminum file. I have used it on lead before and it was fine for cleaning up a casting flashing.https://www.airgas.com/product/Tools-and-Hardware/Abrasives/Other-Abrasive-Products/Burrs-&-Kits/p/RAD64006925?fo_c=306&fo_k=32a174ee0a1c82f843e160cf27a23dcc&fo_s=cstmc&s_kwcid=AL!10136!3!416301623456!!!g!812444800533!&utm_arg=SEM:Google:GSN_-_Items_-_Tools_and_Hardware-Other_Abrasive_Products::pla:pla:Airgas:tools_hardware::RAD64006925::PLA&gclid=EAIaIQobChMIz9GL3Jnx6gIVlozICh3Ndgq2EAQYEyABEgKIm_D_BwEbeware, some of the Al burr geometries for aluminum are seriously expensive ($60 vs normal $20 radnor burr vs $5 ? chinese one). The aluminum burr must be harder to machine (perhaps mass production machines don't exist for weird Al bur geometries)?I got deburring tools, and its definatly worth to get the expensive ones made in USA. I had a bag of like 30 Chinese ones, and they are just utter junk compared to quality tool manufacturer one ( I mean manual deburring 'scythe' blade). I put a fresh one on, and it still ran horribly. I got two deburring tools, one at sears (still kinda shady) and some crap off eBay, I used up the Sears blade eventually, and I switched it to the eBay crap blade, and it just felt broken.. so I ordered much more expensive good ones.I want to literary throw away the cheap ones.. its like using 'magnetic' (steel) fake copper wire in a lab.. get real china.. One of the worst Chinese tools I have used. Way worse then something like pliers that don't align perfectly or whatever, they just suck. Not a trade off that can be compensated for unless you know how to sharpen them with diamonds or whatever is used to sharpen it.Probably not worth your time unless you are really into sharpening stuff?I also wonder how many people think the manual deburring tool is trash because they used a trash blade on it.

author: bill_c
author_rank: Regular Contributor
timestamp: July 29, 2020, 01:35:04 am
content: You need very sharp cutting edges to get a good cut on aluminum. Trying to use the aluminum cutting tools on steel would quickly put an end to that sharp cutting edge. Using steel cutting tools on aluminum does work, may not cut as cleanly, will tend to smear the aluminum and make it stick to the tool, but shouldn't hurt it.

author: eKretz
author_rank: Frequent Contributor
timestamp: July 29, 2020, 05:35:03 am
content: The edges on all burrs should be very sharp. You don't want to use a burr that's been used for steel on aluminum, as the steel will start to dull it right away and once that's happened it will build heat quickly and really make the aluminum stick to the teeth. Burrs specifically for aluminum have more widely spaced teeth and the gullets are more smoothly curved - shaped so the chip flows more readily and doesn't have any easy place to get hung up.

author: coppercone2
author_rank: Super Contributor
timestamp: July 29, 2020, 05:44:30 am
content: how long can a burr grind anyway? Carbide on mild steel I guess is the case.

author: KL27x
author_rank: Super Contributor
timestamp: July 29, 2020, 07:32:04 am
content: QuoteNo. I thought I ruined my first carbide endmill cutting MDF. Then I looked up the melting point of tungsten carbide.It was just resin.I have lost a burr by letting the bit get away from me in a tight spot, bending the steel shank. And I lose some by losing them. But I have yet to throw one away because it's too dull. I guess it depends on your stinginess and patience/expectations of material removal rate.

author: KL27x
author_rank: Super Contributor
timestamp: July 29, 2020, 07:44:21 am
content: QuoteYeah. Aluminum is gummy and stringy and wants bigger gullets and all. But (I think) you also have to take a bigger bite of it to get a chip. Else it smears and creates a lot of heat. Aluminum puts you between the rock and the hard place when your cut is flirting with your max power. If you can't maintain that cut, then you instantly go from cutting to burning your stock and cutter up. Sharpness helps with getting that bite when you have limited feed pressure and horsepower and/or high surface speeds and/or you want a good finish.When cutting it with a bandsaw, for instance (if you don't care about the finish, that is), you don't need a very sharp blade, at all. As long as you have a low enough TPI on your blade and enough stiffness of the blade, you can take big enough bites to not overheat. The faster the saw runs and/or the less HP that it has? The lower the TPI you need. You need to reserve that power to actually get fewer bites per second, rather than more smears per second. So the wider tooth/blade spacing on aluminum cutting tools is not necessarily done only for a larger gullet. For a given scenario, you might be using only half your gullet capacity, but you still need a lower TPI. But you might as well enlarge the gullet while you're at it, if the blade has the space for it. That gullet isn't helping, here, but will allow you to also cut thicker and softer materials. So for lower HP you might need bigger (technically wider-spaced; bigger is a side effect) teeth. It's extremely non-intuitive, isn't it?

author: duak
author_rank: Super Contributor
timestamp: July 30, 2020, 05:56:28 am
content: Some ruminations on metals and machining them. I do a bit of electronic work at a CNC machine shop and have picked up some nuggets of info over the years.For soft al and copper, it'd be good to have a gullet as open as does an end mill but even the Terminator would have trouble hand holding a die grinder. I think it would tend to bounce and dig. Cripes, I knocked a few teeth off an expensive bur after a few bounces in a confined opening. Here's a bit of info on bur type and appropriate materials:http://www.grobetusa.com/content/burcuts.pdfThe thing about burs (and other cutters) for various materials is how grabby and gummy the material is. Al 6061 is nice to machine (not that grabby like brass) but it can quickly clog a tool (gummy). CNC mills shoot water based coolant into the cut to blow the chips out before they have a chance to stick to the cutting edge. The tool path almost universally down mills so the cutting edge makes the fat end of the chip first. This tends to pull the cutter into the material which is no problem unless there is play in the machine feeds. The chips tend to be thrown away from the cut. Conventional milling, where the thin end of the chip is cut first tries to push the material away. It also pushes the chips ahead of the cut and unless removed, will get drawn back in and be recut or packed together. When that happens, softer materials get smeared on the cutting edge and will quickly build up and clog the cutter.Copper is a total pain to machine because it is grabby and somewhat gummy. Some machinists have modified drill bits for brass and copper that don't have the sharp edge that undercuts the material and makes the drill bit want to screw itself into the material. It is more square and almost scrapes its way in. One machinist actually ran the bit in reverse to make holes in a particular piece.Titanium needs a large depth of cut. If you baby it, it will work harden and you will not easily get through the hardened skin. Most stainless alloys are the same. Titanium and copper will also squeeze and then grab a drill bit right out of a holder or chuck as they close down on the tool. You do not want to stop and linger to clean out the chips when reversing a tap. It's a problem as taps will often break when trying to wind them back out and the relief on the backs of the flutes packs cuttings between the tap and the walls of the hole.

author: coppercone2
author_rank: Super Contributor
timestamp: July 30, 2020, 06:40:32 am
content: well, i notice on the freshly welded aluminum, so long you pour alot of oil on the weld and the burr before you start, the double cut carbide bur works well, but the problem is.. oily chips. Their utter bastards to clean up. You also need to reapply oil alot. So spray can is your friend. I hope the alumicut works dry.those bur geometries are very complicated and I think you would have a horrible time trying to modify them for different metals.

author: duak
author_rank: Super Contributor
timestamp: July 30, 2020, 08:20:22 pm
content: Manual work with aluminum often only needs a few spritzes of coolant from a sprayer to keep it from sticking. The shop gets drums of Fuchs Ecocool (I don't know the exact product) and mixes in water for use in the machines. I don't know if Fuchs (or others) can provide smaller than drum quantities of coolant premix but if there's a machine shop nearby, you might be able to hit them up for some.https://wwwfuchscom-94ba.kxcdn.com/fileadmin/schmierstoffe/Prospekte/Brochures_EN/Product_brochures_industry/Wmb_Nwmb_KSS_EN_SQ.pdfAs I said, these coolants are water based and I understand they start with a water soluable or miscible oil and then add various things to stop rusting, keep microorgansims from growing and keep the oil from separating out. If you aren't familiar with it, it looks like milk. I have a small workshop at home so when I need a bit of cutting coolant I just get a bit from the CNC shop. It's water based and basically just rinses off unlike neat (100%) oil cutting fluids.Some home CNC people whip up their own coolant from Canola oil, dish detergent and water.Cheers,

author: jpanhalt
author_rank: Super Contributor
timestamp: July 30, 2020, 08:52:41 pm
content: On most soft aluminum, kerosene/diesel will work well. Of course, as I said before, "aluminum" can be one of very many alloys with different properties. You need to know which alloy or alloy group you are machining. Copper is also mentioned. Again, there are relatively easily machinable copper alloys and then there are ones (like pure copper) that are difficult to machine.Based on your numerous other threads, I suspect those important differences have escaped you.

author: coppercone2
author_rank: Super Contributor
timestamp: July 31, 2020, 01:09:56 am
content: Quote from: duak on July 30, 2020, 08:20:22 pmi think this depends on the geometry of the cutter, as someone here said I don't think you can hold the cutter designed the effectively eject aluminum on a milling machine with your bare hands, its going to be some kind of compromise

author: eKretz
author_rank: Frequent Contributor
timestamp: August 04, 2020, 10:08:28 am
content: WD40 actually makes a pretty good cutting oil for aluminum - prevents chips sticking to the tool quite well. There are a lot of intricacies when cutting different materials in the machine shop, but those aren't really relevant in a discussion on using carbide burrs on aluminum... If you want my number one bit of advice on using carbide burrs in aluminum, it's to use a slower grinder. Rather than futzing around with hosing everything down with oil and creating a bloody mess, just use a slower grinder with a proper burr made for aluminum use and it will prevent most of the sticking without your needing to resort to the WD40. What RPM is the die grinder you're using now?

author: coppercone2
author_rank: Super Contributor
timestamp: August 04, 2020, 05:52:45 pm
content: Its adjustable speed from 0-25K (I got the milwakee right angle one and the dewalt 60V one, they are variable speed, but they have span ranges (so you can cap it at 10k, 15k, 25k))Damn these aluminum burrs look grizzly. I opened the Radnor pouch and it punched me in the face. When I saw it I was convinced they sent me 3/8 ones till I saw the shank (it is correct). They look like they will fuck up metal good. They look like worm gears almost. Very mangley.What range should I stick to?

author: KL27x
author_rank: Super Contributor
timestamp: August 04, 2020, 07:24:25 pm
content: By hand? You'll need higher RPM because you lack rigidity and low speed power/torque/inertia on that tool.You also need to be concerned with concentricity and runout and vibrations. When it comes to rotary tools, these standards are very low, in general. I've mentioned before that for free-hand milling, I doubt your Milwaukee can keep up with a much lower power Proxxon tool. I would reckon that this is what's limiting your cut rate, at this task. But I've never used the Milwaukee.I believe these burrs are probably optimaized to run at ~25-30K rpm, because that's where die grinders live. A proper electric die grinder will cut steel, wood, and thick plastic probably 10x faster than a proxxon, and a proxxon will cut steel 10x faster than my own Dremels, using a burr (with a cutoff disc? Dremel 2-3x as fast as the proxxon). Never used an aluminum burr, though.To hog aluminum, I would freehand with one of my $25 dollar trim routers. Cuz I'm too cheap to buy a proper die grinder (the cheap die grinder I bought is crap). Proxxon for fine work.;;;;My cheapo die grinder has excellent concentricity and runout when measuring it with a dial caliper and turning the bit by hand. It's perfect as far as my ability to measure, so I couldn't ask for better at any price. But the vibrations from the poorly balanced motor throw that out the window once you turn it on. Hence, it won't cut well with a bur. It won't cut for shit with a bur, probably conveys things better.

author: coppercone2
author_rank: Super Contributor
timestamp: August 04, 2020, 09:26:47 pm
content: https://www.milwaukeetool.com/Products/Power-Tools/Metalworking/Grinders/2485-20*warning before buying like I did, this thing seems to have some reliability issues. I hope for the best. But I think its because people are mistaking it for a polishing tool or sander/burnisher or something. I think its not designed for that.It was doing aluminum OK with the carbide burr. But these do look like it requires the bigger one maybe. Claims to be stronger then the pneumatic one anyway.. but i never used pneumatic tools. It does OK on steel for small things and it was working ok with aluminum on the carbide burr but these burrs kind of shocked me with their appearance. I will see.What is the proxxon 1/4 inch die grinder? i did not know they made one.example of burrhttps://www.walmart.com/ip/Radnor-SE-3L6FM-3-8-X-5-8-Oval-Shape-Aluminum-Cut-Carbide-Burr/171259153BTW all these battery powered die grinders have heat issues, the dremel, the dewalt, the milwakee. Particularly it seems to show up when you use them at lower speeds. Tempting to plug it into a air compressor for cooling LOL. Not the most achievable design. The most power hungry application I have seen on these tools seems to be using the black-spongelike stuff for removing paint (excellent tool to salvage 'charnobyl' junk but you need to keep the thing you are working on dry and cool enough not to make the paint mushy).

author: KL27x
author_rank: Super Contributor
timestamp: August 04, 2020, 10:55:55 pm
content: Proxxon doesn't make a 1/4" version. I use 1/8" and 3mm shank burs in my proxxon tools,. I use 6mm and 1/4" burrs in my trim routers-as-grinders. You can buy a wide variety of burs in 1/8"/3mm sized shank for detail work.Re milwauukee: Oh, well that appears to be meant as a die grinder. I hope it would work better than the average rotary tool. I was under the impression it was a rotary tool.But compared to any typical corded die grinder that thing looks tiny. Tiny tool, tiny inertia. The motor mass on a typical electic die grinder will dwarf that Milwaukee. Pneumatics suck a crapton of power to do what they do with such little mass. This looks more like a cutoff/sanding tool with an optimistic marketing department.;;;QuoteAt lower speeds, esp, yeah. The controller probably waste a lot of power as heat (and/or maybe the lower speed resulting in lower inertia leads to more power consumption and lower relative efficiency?). My makita router warns, in the manual, that low speeds are only for short duration use, or the controller will burn out.Last thing I did with a rotary tool was to turn a 6 tpi 1/4" bandsaw blade into 3 tpi, which I can't find anywhere that sells such a thing. (And I have half a roll of 6 tpi). I tried almost every rotary tool I had. The dremel cut the fastest (with cutoff disc), but it would only do 3 teeth before I had to stop; the plastic housing got too hot to hold, and I couldn't manage it with the welding gloves I have on hand. One of my proxxons worked, but I had to hold it funny so the vented hot air didn't burn my fingers (plastic housing stayed cool). The only one that made it practical was my cheapo Proxxon where the vents are further back, overvolted about 33%. Did the whole job in 10 minutes without stopping.

author: coppercone2
author_rank: Super Contributor
timestamp: August 05, 2020, 01:09:53 am
content: i kind of wonder if blowing air into the vent with a air compressor is a good idea? are you putting more stress on the windings with rapid cooling?or better to run it at no load for a little bit?but do keep in mind for electric, those are brushless motors.

author: KL27x
author_rank: Super Contributor
timestamp: August 05, 2020, 01:20:56 am
content: Dunno. I'm not sure where the air goes in, on these things. And my air compressor wouldn't keep up a decent stream, anyway. 2.6 CFM at 90psi? Not a whole lot, there. It's crazy how quickly my Dremel gets hot when you're cutting fast. But it's really old. My worn out Proxxon also gets hot in seconds, so I can't put that all on Dremel, considering the age. I think I've that that Dremel for around 15 years, now.

author: coppercone2
author_rank: Super Contributor
timestamp: August 05, 2020, 01:52:53 am
content: i imagine the intake is the bottom slots because otherwise it would pull dust in.i have when frustrated stuck the air blow gun in there and blew it out, you get a burst of hot air from the top. I do this on the milwakee 1/8 grinder tool when using it with mini flap wheels for glue prep or corrosion spot removal (it seems to heat it up alot).I kind of get the feeling though, that using fresh sharp sand paper by hand makes for better glue prep, or at least after the machine sanding, to go over the area with fresh sharp paper. It has to be the sharp kind. Machine does not solve all these issues I think.I..e for plastics bonding (have fallen in love with the glue mix applicator from 3M)only problem is applicator cost, but I can lay down the glue lines like the pros do it pretty easily for 50 cents. If you have a long cure time epoxy, you can actually put the whole gun in the fridge, do a oven cure on the part, and keep working (all depends on the time required to get handling strength in the part you want).

author: eKretz
author_rank: Frequent Contributor
timestamp: August 06, 2020, 03:16:50 pm
content: Quote from: coppercone2 on August 04, 2020, 05:52:45 pmI would start at about 15k and see how it goes. Your burr diameter plays a role in the right speed selection just like with any other cutting tool. Cutting speed for carbide tooling in aluminum is generally in the 800-2,000 SFM range. So for a ⅜" burr that's approximately between 8,000 and 20,000 RPM. That's for hogging off some metal. You can run a little on the higher end if you're just lightly dusting.Your grinder is probably a lot less powerful than what I'm used to using, so not sure how well it will do. I normally use a 1 HP Dotco air die grinder, it's a beast. For hog grinding, I generally lock the back of my left hand down to the work and let it act as a pivot, holding the nose of the grinder right behind the tool. Right hand operates the throttle and controls the very back of the grinder, if I need extra rigidity I will position the bottom palm of my right hand so it is resting on something solid also.

author: coppercone2
author_rank: Super Contributor
timestamp: August 08, 2020, 11:17:58 pm
content: the aluminum burr works well on the small die grinder with 15krpm with minimum chip build upStill probably could use a spray of oil though. Run dry the double cut one would be clogged in the same amount of time as this only had a shred on one of the cutting edges that easily came off.

author: eKretz
author_rank: Frequent Contributor
timestamp: August 09, 2020, 11:15:34 am
content: Try dropping to 10k and see if that is even better. I definitely wouldn't go any faster than the 15k if aluminum is starting to stick to the teeth a bit. Part of the equation at preventing sticking with gummy aluminum (if you've gas welded it, it will be pretty gummy) is keeping the heat down.

author: coppercone2
author_rank: Super Contributor
timestamp: August 09, 2020, 04:58:44 pm
content: mm that little tool is going to have problems at 10kRPM in terms of heat, the big one should do better. My plan for having both was so that I can fix two different burrs on them so cleaning is easier. The gas weld puddles are not very uniform so sometimes it seems to make sense to switch tools, or to cut a small path for the bigger tool to sit in better (easier control).

author: eKretz
author_rank: Frequent Contributor
timestamp: August 10, 2020, 04:39:38 am
content: And now you see why most machine shops or fab shops that do a lot of die grinding use mostly air tools. Generally, they cool themselves with the air flow. Corded electric are better than cordless in a lot of cases.

author: coppercone2
author_rank: Super Contributor
timestamp: August 10, 2020, 05:49:34 am
content: the air compressor is not acceptable due to noise for most people that are near otherssort of feel bad for people with big compressorsactually impressed with the little tool, I ran it on the low RPM for a while with the small battery and it did quite a bit of work on making a hole on something that tapered from 1/4 to 1/8 or so. ( 1 inch by 2 inch hole, but it is an 'ovalish shape' so I decided to file the entire thing out after doing markup with a engraving tool. Its an odd piece (rejected boeing airliner commercial part given to me as scrap, looks a bit like a die-cast model car lol). Very happy to make use of it finally, as a torch holder, because I thought it would outlive me in the scrap pile. It will look flashy since its nicely fly cut in certain places and machined in other places etc.The die grinder has more power then the same abrasive mini cutoff tool that runs on the same battery in terms of cutting aluminum. It's actually decent. Or at least, I think the cutoff tool is hitting its stall because its not equiped with a aluminum cutting wheel.However, after making said hole, the battery was almost too hot to touch lol. No aluminum stuck to the new burr either. Not absolutely sure the lower speed is better, I feel like I had more control with the higher speed. However I will say the process is now pleasant without spraying and grease and checking for clogs etc.

author: eKretz
author_rank: Frequent Contributor
timestamp: August 10, 2020, 07:31:59 am
content: When working by hand, it's often a compromise between control and optimal tool speed. Similar limitations can come up when using machine tools that are manuallly operated vs. CNC. Another tip that might help your tool life is to always keep the tool moving. Don't let it dwell in one place any longer than necessary, preferably not at all.The better compressors actually aren't that loud. Low priced oil-less models are the worst offenders in that respect. I took a 47CFM compressor head I got at an auction and run it at 1/2 rated speed to get about 23CFM and it's pretty darn quiet for that volume. Much quieter than my prior Ingersoll 16CFM.

author: coppercone2
author_rank: Super Contributor
timestamp: August 10, 2020, 10:10:30 pm
content: on the medium speed this thing is eating aluminum on the little right angle 12 volt die grinder like nothing. Battery did not get warm etc. I think its a really good tool. The removal rate makes me almost feel like im watching someone use a bridgeport mill on youtube (like, at least it comes to mind, vs proxxon micro-mill.. which is more like a dremel )I removed like a 2x2 area of aluminum with thickness between 1/8 to 1/4 with it, and the smallest 12V battery (the compact one that hides in the drill) is still at 4 lights.I do wonder how much more fucking utility you can get out of a dremel if you used it with a 1/8th inch aluminum burr rather then using the carbide metal burr on it. The bigger less oval shaped cutting tools on the dewalt die grinder are a bit harder to control, I can actually use the milwakee tool as you are supposed to use it, without bracing yourself, to do things like deburring, but with the bigger dewalt tool on the bigger burr I need to find a place for my forearm to make a lever, otherwise the pressure is not good and it kicks out of the hole (bad).

author: MarkMLl
author_rank: Frequent Contributor
timestamp: August 11, 2020, 03:57:29 pm
content: There was an interesting letter to Model Engineer 20 years ago. Somebody went to clean up some rust using his linisher, and suddenly found his hands in a fireball: it turned out his son had used it a day before for aluminium.And everybody knows that happens when you mix aluminium powder and iron oxide powder.So whether or not it's something you're supposed to do, and whether or not it actually works, FFS clean up after yourself! :-)MarkMLl

author: eKretz
author_rank: Frequent Contributor
timestamp: August 11, 2020, 04:19:37 pm
content: Incidentally, I've seen that exact thing happen when some knucklehead had ground on aluminum with a bench grinder... Afterward someone else ground some steel and the sparks ignited the mass of mixed aluminum and steel grinding swarf into a pretty little fireball. Luckily there wasn't much aluminum there so it only lasted a second or so and didn't destroy the grinder.

author: coppercone2
author_rank: Super Contributor
timestamp: August 11, 2020, 11:43:26 pm
content: i did not think that could actually happenThermite usually needs decent mixing and packing and alot of heat to ignite.But I do use a vacuum cleaner with my linisher (I think it extends the life of the bearings). Perhaps the vacuum itself...ordered H&L adapters for the linisher disk (long overdue, I never even use the fucking disk because standard procedure is to use a scraper, mineral spirts and heat gun to change a sanding pad !!!wtf is this shitwho does this on a regular basis?when I saw this 5 years ago I thought I got scammed!) *, going to replace the belt and take it apart and wash/wipe it down and clean out the hoses to be safe.I think I changed that disc sander paper like twice in 5 years.electronics engineer : complain about 2 turn screw on soldering iron station, spend 600$ on a hot quick change PACE station, sit on CAD most of day then end up ordering a PCB ready made, then fight over position of small 'ant' on 'cracker' for 2 weeks in email. Get project canceled because it has too many 'ants'. Then hide in cubical, afraid to go to the water cooler.carpenter : conduct multi process multi tool operation complete with chemical disposal and gloves (in the state of california) for sand paper change that needs to be done after 20? minutes of regular use to make a chair leg, then sell $500 chair. Then enjoy a beer.*I think its because the adhesive will do a better flattening to fit things, but in most cases I use my machine for deburr/surface finish, so I don't want to deal with this hassle.

author: eKretz
author_rank: Frequent Contributor
timestamp: August 12, 2020, 06:45:37 am
content: It absolutely can happen. And the finer the particles, the easier they are to ignite. I am sure the grinder hadn't been cleaned since the last wheel change and the grinding swarf was probably packed into the wheel guard and had plenty of rust packed in there from sitting so long. I read an incident report once about a guy who got enough of a thermite type fireball from exactly that, that he got first and second degree burns all over his hands and face. Might have been on OSHA website, don't remember.And I'm cringing watching that guy in your video use sandpaper on the aluminum disc that's half covered with adhesive. After a few times doing that the disc would be way out of true.

author: coppercone2
author_rank: Super Contributor
timestamp: August 12, 2020, 06:52:14 am
content: don't blame him, scraped that shit today and I had to use a giant acetone soaked rag and a scraper tool for a while.i think the blood was flowing through my body in steam formif you are actually trying to get something finished and you need to deal with that disc I pitty you

author: KL27x
author_rank: Super Contributor
timestamp: August 12, 2020, 06:51:25 pm
content: Dunno if there's something extra special about the larger sanders. Velcro? No way. I use my disc sander to make small edges and surfaces flat; it's a shaper, not a surface finisher. The give in velcro is good for a surface sander, orbital or whatnot. And it's way more expensive.I have just a combo sander with a 6" disc. I experienced many flying discs, trying to take too many shortcuts. But the minimum cleaning is actually very easy. All I have to do is peel the old disc off, then wipe the platen with acetone on a rag. Instead of removing the table, I just rotate the disc by pushing the sanding belt with my other hand. Done in a few seconds.If you get the kinda mess that Ethan shows in that video, try a handful of sawdust wetted with acetone. I should put that in caps and bold, it's so boss at cleaning this kind of residue. Just rub it against the platen. Then scoop up the dust and do it again. The residue will disappear so fast it's like magic. Instead of smearing it around and around, it peels the residue straight off. Watching him try to sand it off is total facepalm salesman BS. Put down the scraper, put down the rag. Pick up the sawdust. Same thing as a rag, you think? No. Remember this sawdust and acetone trick. The day you try it will change your life and your understanding of the universe. I.e., this is going to blow your mind.This will also work on glass, wood, and acetone-safe plastics, like PET, HDPE, Delrin. For other plastics, substitute alcohol for the acetone. If you keep your shop (and your dust collector) super clean and don't have any sawdust? Stop and make some. It saves that much time and effort.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 12:12:31 am
content: what is this saw dust stuff, its all aluminum lately. Your idea reminds me of the sawdust + acetone mixture that people advise for removing oil stains on garage floors.That is a interesting idea and if I ever get another disc sander i might leave the PSA on it, because the money is already spent nowI like it because I can put a finer grit on the disk then the belt and have something at a higher surface finish with two machines near each other, but I see your point.I think im going to make a magnetic snap on cover on the disc anyway, because the little thing near by is more useful as a small shelf to me lolI like the idea of getting a disc sander thats outwards facing (the side direction is not too useful where I have it setup), so maybe a bigger one like a 12 inch for facing, one with variable speedI wanted this one maybe,https://www.homedepot.com/p/RYOBI-4-in-x-36-in-Belt-and-6-in-Disc-Sander-BD4601G/205509608?g_store=6204It has the horizontal belt sander and a more accessible wheel. I have the porter cable one right nowhttps://www.lowes.com/pd/PORTER-CABLE-5-Amp-Benchtop-Sander/3163789?store_code=3248and another one that moves up and down (oscillating), but I am lacking in anything with overhead capability for working on large pieces.Perhaps the velcro would not be too bad for doing finer sanding work with discs on surfaces faced with a PSA one at a courser grit without ruining the face? Like 180+? So keep the potential PSA sander at 120 grit, then do higher grit work on the velcro one, if the need arises to have polished faced surfaces?They sell velcro 8 inch disks up to 800 grit. If it worked, it would be easy enough to switch disks and keep the discs in a binder so I can do a 800 grit polish in a reasonable amount of time without messing with fixturing and the oscillating sander? Kind of wonder at what grit the velcro stops mattering. I thought I could gain a speed capability with this...And I have been using ABRANET up to 1200 grit, and its life time seriously impresses me. I ran out of one of the disc types for the oscillating vibratory hand sander (only got 5x 1000 grit ones), and bought a cheap kit that has up to 3000 grit with normal discs, and I am so disappointed by their life time compared to the mesh discs that go over the 'extractor' velcro on the hand tool. The 1000 grit mesh disc works for so much longer then the non mesh disc. Fills my trash can up fast. And its more dusty.. I feel like I get almost zero dust when its hooked up to the vacuum on the velcro mesh discs.Note: I did not get mesh 8 inch discs for the bench sander, their solid backed, because I tried to 'mitigate' the damage to capabilities caused by the velcro backing.. it should work better if its on a stiff backer even on velcro, for facing.. but the life time is so crap. Mesh + velcro is basically a polishing sponge... but on the oscillatory sander, the mesh feels sharper longer and does not clog so much so long you don't use it on sticky materials (like bad cure). But I love it also for brackets, because they only need 2 flat surfaces, everything else benefits from polish/curve IMO. And I seem to end up making alot of brackets. Oddly enough, in my shop, I don't have that high a need for actually flat edges.........The oscillating bench sander (rigid) has a good mechanism for switching belts, but they only sell fairly coarse belts for this*. And, the dust removal is not that great compared to the waterfall belt sander. The dust extraction on the rigid oscillating sander is not that great, it piles up dust behind the work piece, whereas the porter cable sander seems to extract most of it.*at least locally. I bet online they have some awesome polishing belts. I might look into this because I have a feeling it will be a beast for cleaning up edges if I got a scotch brite sanding belt.......... I should look into this because i Hardly ever use that machine.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 12:44:44 am
content: Also, do you have a sanding belt storage solution? They seriously piss me off in terms of how much space they use. I try not to kink them and it ends up being ridiculous compared to any other consumable I use. Almost feels like I need an abrasives shed.Can you.. safely tape these yourself some how? If I could store them flat, and tape them as needed, I would buy it in like every grit and actually use it, for the 4x24 ones. Transparent gorilla tape? That would actually be a huge shop upgrade.https://www.toolbarn.com/metabo-623530000.html/?gclid=EAIaIQobChMIocP23fuW6wIVJYFaBR2TWQodEAQYASABEgJtKvD_BwEtoo good to be true? Do you think it would last as long as a factory taped one?And another reason I don't keep this around, is because they have a small shelf life.. its one of the only abrasive materials I hear people complaining about life time failure.. abrasive belt bond failures is a topic common to carpentersbut the belts do nest together in some degree, and you would need at least one of each belt thats bonded, so its not really relevant unless its some kind of post apocalyptic 30 year plus belt stash that you need stored in minimum space.

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 04:08:04 am
content: Damn, you're a chatty kathy, today. Read most of that, but a bit of skim.My solution? I have cast iron combo sander more or less just like that Ryobi. What is good about it is that 6" PSA disc are as cheap as toilet paper. And as mentioned, I have never had to use a heat gun, and what little residue is easily cleaned.Different grits and belts? Hell, no. I have an 80 grit belt on there, only. Why 80? Because I tried a 36, and that was too coarse to be useful. 80 grit was the next best deal at the time.I have 80 grits PSA discs, period. Why 80? Because they were cheaper than the 60 at the time. Finer? I don't see the point on a disc sander. I shape things, make them square, make them flat. The miter thing? I use that all the time on the disc sander. By moving the piece across the face rather than jamming it in one spot, it gets smooth enough. If that isn't smooth or shiny enough, it takes nothing to finish by hand, from there! Hand sanding, files, stones, etc.Spare belts? I haven't changed the belt on my sander in 10 years. I do most of my shaping with the disc sander or other tools. The belt only gets hit when I want to kinda smooth over a larger piece of wood and don't wanna bother with the hand plane. I have considered disconnecting it from the motor, because I rarely use it. And it tends to collect tools and clamps on the belt, which I usually notice before using the disc sander.But sometimes I do need it.

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 04:17:17 am
content: If you want to work with aluminum, I think this is the wrong tool. The belt is too slow, not enough power. You want at least double the horse power higher surface speed, and with a longer belt to keep it cutting without having to constantly shift the piece. The belt sander on mine is nearly useless for metal. The disc is pretty decent for small metal work.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 04:35:37 am
content: I find the diablo sanding belts eat aluminum and even steel with little problem for things i like, like putting rounded corners on stuff. (i.e. making a aluminum angle iron that is used to offset a heatsink from the chassis to follow a circles 90 degree arc).Have you ever tried any of the 'premium' abrasives? I bought the e-bay cheap shit before and I was extremely let down by the performance and how fast it dulls. I am worried we are on the wrong page in terms of capability.For instance, my big pack of 'cheap' finishing disks that go from 1000, 1200, 1500, 2000, 2500, 3000 grit, for pennies on the dollar compared to the premium brands, basically I want to throw them away because the performance is so poor.https://www.diablotools.com/products/DCB130VGPS03GI don't think its good enough for something like bladesmithing, but I find it very capable. I never tried cheap sanding belts before, but I am worried we are on a similar problem as the deburring tool.I said in another thread, I bought a 'value pack' of super cheap carbide sharpening tools and they were basically garbage, akin to steel test equipment wire (the fake banana plug shit on ebay that has the wire attach to a magnet). I watched alot of 'grinding doctor' videos on youtube and I Have a feeling there might be something in it.What I am still not sure about is polishing medium, I don't know if something like the jewelers rogue from harbor freight is any better then a high end expensive one from 3m. Hard to imagine but I never bought the good one.Example of where I like polishing using a sander belt : small welded RF box that needs to look nice on the outside. Most people don't have this need because they bend stuff .And I feel extremely not impressed by cheap flap disks, i order norton and wait for a box rather then HF. Not sure how the diablo ones compare, home depot started selling higher quality ones now.. but I believe in walter

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 04:43:35 am
content: No. I don't buy "premium abrasives." We went through with 3 years ago with your "premium" flap discs that wore out just as fast as normal ones.Abrasives can be tweaked to perform better at specific things, esp when you make the test like a robot. But it's just an artificial test. Until you have some production use that gets performed like a robot by people who have to do things with guides and won't pay attention to what their doing, it probably doesn't matter. That much.E.g., Fireball's belt grinder challenge. He tests his old grinder by pushing the 1/2" mild steel rod straight into the belt, with the rod flat against the table. Then he tests his DIY 5 HP belt grinder by tilting the rod 15 degrees off the table and both sliding the rod back and forth against the belt and twisting the rod. No duh it will grind at least 3x as fast just by doing that.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 04:46:52 am
content: I also used both and with the same technique I thought there was a drastic difference in usable life expectancy between warrior and walter.But I also think its possible to quickly trash both to a unusable state if you grind dirty crap. I think alot of tests are contaminated by millscale.. nothing can deal with that goodBut seriously, belt sander on aluminum, a wood workers tool is good for everything save for fixing a russian BMPI saw extremely high powered equipment before (giant band saw the size of a car) that had very impressive speed, but it was ridiculous. You need a cabinet factory to justify it.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 04:51:56 am
content: I do agree that the static tests using a grinder are very poor because when you use it, you sway to the pressure, its very difficult for a simple machine to duplicate that.

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 05:01:57 am
content: If I cared to smith a blade, I would be using rotary grinders, the most. Maybe only very short visit to my under-powered belt sander on really large blades, only. Then time with files, stones and sanding blocks. I ground some really poorly profiled knives on the belt sander, ages ago. But that was before I had an angle grinder. That would have gone must faster, today!E.g., I repaired my GF's lawn furniture a couple years ago, and I need to pull about a hundred staples. I just ground my smallest chisel into a staple puller with the angle grinder. After the job was done, I ground it back to a chisel in about 20 seconds, using the same. Shaving sharp from there in another 2 minutes on the stones.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 05:10:14 am
content: btw nothing we have is expensivehttps://www.toolfetch.com/Pferd-84349-4-OD-Diamond-Coated-Wire-Cup-Brush-400-fine-grit-5-8-11-thread-PERFECT-MI?utm_source=google&utm_medium=cpc&adpos=&scid=scplpPFD-84349&sc_intid=PFD-84349&gclid=EAIaIQobChMIoozt_7SX6wIVWQiICR0CPgwBEAQYAiABEgIXmfD_BwEthats expensivethey should throw in a free angle grinder with that.I assume you might use that working on a underwater pipe line repair or some crazy expensive per hour thing where they don't care about anything but time.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 05:39:20 am
content: Quote from: KL27x on August 13, 2020, 05:01:57 amhoney, you need to buy me this tool to finish the jobhttps://www.homedepot.com/p/Milwaukee-M12-12-Volt-Lithium-Ion-Cordless-3-8-in-Crown-Stapler-Tool-Only-2447-20/302652845for 100 staples, I would buy that actually LOL. Next time I redo a sheet rock exterior wall...did you use monel staples to finish the furniture?

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 05:52:50 am
content: ^I bet it would take longer to learn how to get it to work 50/50 than finishing the job using a sharpened piece of steel with a handle. You ain't one of the "Red Club" cultists, by chance?I would have rather paid someone the $100 bucks to have that job done for me. Oh, I guess it would be like $250 by the time I bought the charger and battery? No wonder the cult mentality. Once you buy in, it's Red for life.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 06:02:14 am
content: red yellow and orangeI won't stop talking shit about the milwakee metal cutting abrasive saw because they used a non helical spring. And its built cheap in comparison to dewalt. Their big die grinder has no safety on it either.oribital sander - inferior to rigidangle grinder - inferior to 60Vchain saw - inferior to 60vUnfortunately its not perfect so I have too many chargers.Only cult I am in is HP (other then power supplies... lambda wins.. they build stuff like avionics grade)

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 06:10:04 am
content: Orange? Is that Hilti?Other than one good cordless drill, I may just cling to my stationary tools, hand tools, and extension cords until the bitter end.I don't have to work outside my own home too often, and if I did I'd probably just end up hurting myself by bringing every tool I don't need and forgetting the one or two that would actually do the job, properly.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 06:57:56 am
content: rigid is orange

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 07:05:42 am
content: Well, now I can say I have never even used a single power tool from any of your favorite brands.Unless you count a Dewalt heat gun (that broke in a month). And I think I own a Dewalt hacksaw.The only premium tool brand I'm partial to is Hakko.And you know I like my Proxxon rotary tools!

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 07:46:07 am
content: I recall you said one time, "I'm afraid to buy cheap shit to start with, because I won't know if it's good. I won't have anything to compare it to."I use a Hakko iron because I solder a lot, and there are features of the Hakko (tip selection in particular) that just make my life better. But most of my power tools just need to get the job done, occasionally. If there's better out there? Just as well I don't know about it. If what I have is enough to make my idea into reality, that's fine. When I need a thousand of them, then I'll look into better options. I don't have that many good ideas, though.Proxxon: There are so many ways a precision rotary tool can get the job done where nothing else can. And I have tried cheapo tools, and it's not even close. Dremels aren't bad, but still not the same.Heat guns, I've killed 4 of them, which is why I tried Dewalt and Porter Cable. Both of those broke faster than the cheapest crap out of China. I didn't cool those down when shutting them off. But if I have to do that, why pay more? The cheap guns last forever when I take the time to do that, too.;;;;;;;;;;;;;;Hammer drill? I have a kinda nicer one, but that's cuz the first one didn't finish the job. One of the only tools I jumped into higher quality from the start was my first jigsaw (lol; is this the worst tool to splurge on?). I wanted a bandsaw, but I lived in a small apartment at the time. So I splurged. At some point, I used a cheapo black and decker that cost 1/6th as much, and the performance was nearly identical! Neither one cuts straight unless you pay attention and take it slow. And now that I have a bandsaw and a japanese pull saw, I never use a jigsaw at all.

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 07:51:52 am
content: good heat gun manufacturers (industrial) sell alot of replacement parts, the technology is such that its difficult to make a long term reliable system in the form factor they want. It has to do with the kiln equations for nichrome wire and 'surface load' of a furnace. You won't find a good one from what I can see. It would need to have a huge heat exchanger to work for a long time. One of the few tools you can buy that the page which sells the tool sells all the replacement parts. Not hidden in the manual on another page, they just expect it to break. I think they want too much heat from too small of an area. Non bullshitters seem to treat the hot air gun elements like projector lamps (everyone knows that they don't last a long time).My cheap -something-master harbor freight heat gun died before the real one did (still working).Another problem they have, possibly, that I noticed from my own work, is that if you have a heater coil, and you shut off the air flow and the heat at the same time, the heater temperature rises quite a bit more (graphed a spike much bigger then the steady state temperature) before it cools down.. so you need to shut off heat before you shut off air flow. Say you put a thermocouple on of those those resistors you can blow air through, you can see this. My portable AC does this, if you turn it off normally, it keeps the fan running for a little bit after turning off the compressor, because the designers knew it would get too hot if you just turned everything off at once.. not dangerously but it reduces the life time I think. Thats part of the reason why a hot air station ramps down, the heater is pretty much in a insulated tube when you take the air flow away.This could be something the chinese noticed that improves the tool if what you say is true, I have not seen it. Makes power interruptions worse..

author: MarkMLl
author_rank: Frequent Contributor
timestamp: August 13, 2020, 08:23:38 am
content: Quote from: coppercone2 on August 13, 2020, 07:51:52 amIs that possible? If there's no energy input and the entire subassy is at the operating temperature I can certainly see that it could take a long time to cool, but I'd have thought that the only way the heater temperature could go up would be if some component was already at a much higher temperature.Or were you measuring IR emission, which was normally suppressed by conduction due to cold air being blown over the heater?MarkMLl

author: coppercone2
author_rank: Super Contributor
timestamp: August 13, 2020, 08:26:23 am
content: i had a thermocouple in a tube attached to a component I was cooling with forced air. I think it was embedded on the surface with epoxy or kapton tape.I wanted to see what happens if you cool something with ducts and a blower. (PVC pipe with resistor in it, big one like 25W)Never gave it much thought, I still have the part I made, I can re test it tomorrow maybe, with a graphing thermocouple meterBut AVE said this too, he said to keep tools running at no load when you are done, so the fan gets rid of the heat at no load, and the reason why power tools die is because people turn them off abruptly after heavy work and there is heat in the system still.

author: eKretz
author_rank: Frequent Contributor
timestamp: August 13, 2020, 08:45:25 am
content: If you want a good polishing compound, skip all the other stuff and get a stick of Zam. Best all around polishing compound for metals I've ever used. Caveat - when using a buffer...

author: MarkMLl
author_rank: Frequent Contributor
timestamp: August 13, 2020, 08:57:46 am
content: Quote from: coppercone2 on August 13, 2020, 08:26:23 amAgreed. But at that point you're talking about- in the case in hand- heat migrating from a filament to supports etc. that can't take it.The idea of a filament's temperature rising without energy input is one I have a problem with.MarkMLl

author: KL27x
author_rank: Super Contributor
timestamp: August 13, 2020, 09:15:20 am
content: I'm not sure what the semantics being argued are, but the filament is what broke in every brand of heatgun I have tried when I don't turn down the temp for 10-20 seconds before cutting the power.Good point on the other tools, when running them hard. I think I watched that vidjaio? I just never remember that.

author: eKretz
author_rank: Frequent Contributor
timestamp: August 14, 2020, 05:56:34 am
content: On the heat gun subject, sure they can last. I've got a Milwaukee 1100°F heat gun that I bought new what must have been nearly 20 years ago. Still works great and has only had one failure - the ribbon cable going to the digital temperature display. And that was just the solder joints cracking. Resoldered and all was well.I have always turned the heat off before the fan to allow the gun to cool down, ever since it was new. And I use that thing quite a lot for all sorts of things, from surface mount soldering and desoldering (made my own much smaller nozzle attachments) to scraping paint to heating plastic for bending to... You get the idea.As far as heat increase after powering down, I've not seen that phenomenon except in electric motors or similar items with a fairly large mass of wound copper wire. In that case, it's due to the fact that there's a large bundle of copper wire inside and fan cooling means the outside layer of the bundle cools first, creating a thermal differential from inside to outside. If the motor is shut down, the higher heat from inside the bundle will transfer out to the cooler outer surface, resulting in what seems like "magic" heating but is really only heat transfer from the warmer part of the bundle to the cooler.

author: coppercone2
author_rank: Super Contributor
timestamp: August 14, 2020, 08:53:28 am
content: yea this thing was beefy, good that someone else saw that because I don't feel like doing it again LOLnot sure if a heat gun bobbin can do that, i sure don't want to measure it

author: coppercone2
author_rank: Super Contributor
timestamp: August 25, 2020, 05:43:04 am
content: does anyone know what the preferred burr geometry is for going inside an interior corner (junction between 3 weld beads?)I feel like what you think works works on a single weld bead interior corner, but when you are doing the corner, where 3 match up, I notice you get alot of vibration and its difficult to align it there. I don't own any but I was wondering, is the ball burr the optimal geometry to use there to knock it down to reasonable geometry before you go in with thinner burrs?In my mind I see the spherical burr being the most forgiving to alignment, especially if you got some weird stuff going on in there because there is so much weld material there. But, is this accurate?

author: eKretz
author_rank: Frequent Contributor
timestamp: August 26, 2020, 02:11:40 am
content: Generally, use the smallest diameter burr you can without risking breakage when working in inside corners. I generally prefer a cylindrical double-cut for roughing-in most of the time, but for a corner where 3 planes meet like in an inside corner of a box, I would probably use a "christmas tree" shape rather than a ball.