milwakee cobalt vs titanium nitride drills - Page 1
Forum section: electronics / general

author: sarepairman2
author_rank: Frequent Contributor
timestamp: April 27, 2016, 12:16:38 am
content: So I own a set of the TiN drills. Every time I go to home depot I see the cobalt steel ones for sale... and its tempting.are they totally better? do the drills have different performance vs different materials?is there like a table of materials to use with the different drill types?Does this sound right? For a guy with a drill press and hand drills.TiN = Limited to Plastic/Wood - not sharpenable , any advantages to HSS besides wear (given their unresharpenable nature)HSS = Aluminum (keep them sharp) (keep polished?) - easy to sharpenCobalt = Steel - can sharpen?Carbide = Masonry, PCBs no clue, disposable/difficult to sharpen.copper? iron? cast iron? plastic with glass beads? other things commonly found? titanium? magnesium? magnalium?is there anything to be said for low carbon steel bits? i.e. for cutting very soft materials (easiest to get a razors edge on?)is there a drill bit compatability chart that goes into great detail about this?

author: Ian.M
author_rank: Super Contributor
timestamp: April 27, 2016, 01:23:47 am
content: TiN (Titanium Nitride) is a very hard low friction coating that reduces wear on the cutting edge by reducing heating and reducing the plucking effect of the chip flowing upwards across the forward face of the edge. It can be applied to high quality drills or to shonky far east sh!t made from recycled bean tins. Black oxide is another surface finish, more usually seen on cheaper drills, and common on wood drills.With appropriate cutting oil, good sharp HSS drills can handle drilling mild steel in thicknesses up to about two bit diameters with no problems. TiN coated HSS will last longer. Stainless steel is more problematic due to its tendency to work harden. High alloy steels are far more problematic, need better than HSS and may be effectively undrillable if hardened.Tungsten Carbide isn't just restricted to masonry, fibreglass and glass filled plastics. I've also had good results drilling hardened steel and chilled cast iron using specialist carbide tipped drills.Plastics and soft alloys are a whole different issue and you generally need a reduced rake drill to prevent grabbing resulting in jamming and even breakage.

author: tautech
author_rank: Super Contributor
timestamp: April 27, 2016, 01:43:02 am
content: There's very little good HSS won't do with the exception of the hard alloyed steels as Ian has mentioned.This is where these specialist bits are needed, the Tungsten being on top of the rest.Other than HSS the cobalt and titanium nitride drills just stay sharp longer.With soft materials that may grab or corkscrew down the pilot hole a drill press is invaluable to retain control.Like all technologies drilling of other than simple stuff requires practice and the gained experience helps reduce breakages, and yep I've broken dozens over the years.

author: exmadscientist
author_rank: Frequent Contributor
timestamp: April 27, 2016, 02:37:59 am
content: Quote from: sarepairman2 on April 27, 2016, 12:16:38 amNope. They will last longer in production drilling in ferrous metal. If you don't have good, rigid tool holding (i.e., a big heavy piece of machinery), cobalt bits are significantly more brittle and thus more likely to shatter. Possibly taking out an eye. Long story short: don't use cobalt bits in handheld drills.Quote from: sarepairman2 on April 27, 2016, 12:16:38 amIf you really want to go there, the Dormer catalog has more information than you'll ever need:http://www.dormerpramet.com/downloads/2015_nafta_dormer_catalog-english.pdf(warning, large-ish file on slow server).I generally think it's not worth buying anything more expensive than HSS unless you have production-grade equipment or very special needs (masonry aside).

author: johansen
author_rank: Super Contributor
timestamp: April 27, 2016, 02:49:59 am
content: I use cobalt drills in handheld drills all the time. I've broken them by being stupid. One of them broke because there was a crack running up the web from the manufacturer, about an inch long, so half of the flute broke off the end.That said, the TIN coated ones are absolutely sharpenable, it is the coating on the inside of the flute that does all the work. the coating on the end of the drill doesn't do much for you. How you sharpen them is everything, and there are about a dozen different ways to sharpen drill bits.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: April 27, 2016, 02:58:36 am
content: You can sharpen TiN drills, you just loose the coating. But since they're dull there's no loss.Pretty much all I drill is stainless, and I can certainly say that there is a big difference among "cobalt" (implies M42 or M35 HSS) and even regular old M2 HSS bits. Any good quality ("real") M2 HSS bit will drill stainless fine with occasional sharpening and any good quality cobalt bits will do the same for longer. However I have seen cheap M2 and "cobalt" drills that won't even touch stainless.Carbon steel drills belong in a museum.Some of the best drills I have just have a black oxide coating, but they certainly were not cheap. The coating doesn't matter much to me since I'm resharpening frequently.But one thing you should look for that's often overlooked is the cutter geometry. Having a split point makes drilling most metals much easier. Drilling stainless with a regular 2-facet chisel tip is impossible because the chisel works the metal. Personally I like to add a pair of corner facets to prevent chipping the edge of the cutter when breaking through, especially when hand drilling.You can sharpen carbide bits with either diamond or silicon carbide. Masonry bits are super easy. PCB drills are so small that it's practically impossible though.Ian M. mentions the rake, I won't get into that much other than to say it's super-important on hard plastics or shearing (makes powdery swarf) metals like brass or most bronze. Adjusting the rake is sometimes called "dubbing" a drill bit. It takes just a few seconds to do and makes a world of difference in these materials.Finally I think people get into trouble with not figuring out their surface speed so the tool isn't run past it's maximum. Google "drill speed chart" if you haven't got one already.

author: Monkeh
author_rank: Super Contributor
timestamp: April 27, 2016, 03:04:07 am
content: Quote from: sarepairman2 on April 27, 2016, 12:16:38 amTiN is perfectly suitable for drilling metal, both aluminium and mild steels (even some tougher alloys and stainless alloys, with care). They can be sharpened, but they turn into boring old HSS drills (assuming they were HSS to begin with).QuoteHSS can be used for steel quite happily.QuoteSure, but make sure you get it right or you'll just get it to snag and explode in your face. You're not likely to need cobalt steel unless you're dealing with strong alloys or stainless.QuoteCarbide = everything. And far too brittle for hand drilling or most low quality presses.QuoteCopper, iron, cast (iron or alu), glass-reinforced plastics, and most anything else non-metallic, use HSS.QuoteYeah, they're great for drilling cheese and giving to people you don't like.

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: April 27, 2016, 03:14:09 am
content: Personally, I would never buy drills from home depot unless no other option.For the material of the drill, you generally match the drill to be harder than than the material you will be drilling. HSS is good up to softer steels. Cobalt can do some harder stuff, carbide generally hardest. As you go up, you go up in cost, decrease in toughness (easier to break, less abuse tolerant), increase in setup requirements (full carbide for example youd basically never put in a hand drill while hss is fine). The coating you go for is generally matched to what you're drilling, some are better for aluminum, some for plastics, some for steels etc....but most of the time doesn't matter unless you're in production. Also keep in mind the geometry of the drill is just as important as the material, a drill intended for most metals can be a very poor choice for plastics of very soft metals.Also cobalt steel is a type of hss (M35 M42)

author: sarepairman2
author_rank: Frequent Contributor
timestamp: April 27, 2016, 03:27:28 am
content: i still want to find a use for carbon steel bits. perhaps teflon drilling?with the really soft steels i imagine you can easily get them literally razor sharp.might as well get the cobalt ones then..the non replenishable TiN coating annoys me.......... pet peeve... does anyone sell a titanium nitride deposition machine? does this also require a surface thickness coating measurement apparatus or do i at least have the luxury of the advanced TiN properties working even at only a few atoms thickness ?that border between production drilling and home stuff and marketing people annoys me. half of the internet says i should be happy with just hss drills.......i think i need a mass spectrometer so i can choose the right drill prior to drilling.............how about lubricants? what lubricants should be used for what drills?can you at least do the black oxide coating at home/should drills by diligently polished after sharpening with rogue? how can performance be maximized?pretend its a 8.5 digit multimeter, we need a drill thread like the ltz1000 reference threadcan all this information be supported by base principles rather then just 'machinist talk'? (which is why i went to this forum rather then some machinist forum), tribology, surface physics

author: Ian.M
author_rank: Super Contributor
timestamp: April 27, 2016, 03:38:29 am
content: Lets not forget cutting oil - its important to lubricate the bit (especially the cutting edge) and control heat buildup to reduce the torque and pressure required, prolonging bit life.The following applies to hand drilling and low-end drill-presses without a cutting lubricant system:For ferrous metals, any oil is better than none, but you really want a specialist cutting oil, usually a dark high sulphur one for general purpose use. If you don't have any cutting oil, try 5% flowers of sulphur (by volume) in dry clarified bacon/pork fat. Drilling stainless without a good cutting oil is a mug's game that eats drill bits, and drilling it dry (without any oil) is desperation as you may not even get one complete hole per bit!Light alloys generally need light oil, even straight kerosene. WD40 works fairly well. Don't use sulphur containing oils on copper alloys as it discolours them and can initiate corrosion.Plastics generally drill well with flood cooling (use a plasticine dam to hold a pool) with a mild detergent solution, though many can be drilled dry. Dry drilling thermoplastics is problematic if you cant keep the speed and feed low enough to avoid fusing them.

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: April 27, 2016, 04:03:15 am
content: Quote from: sarepairman2 on April 27, 2016, 03:27:28 amCarbon - you can use them for anything that is softer and doesn't cause a lot of heat. It would be fine for teflon, but you should change the geometry of the drill otherwise it will feed into the plastic.TiN coating - you cant coat at home. You can send them out for recoat. Most of the time it's not going to make a difference unless youre in productionthat border between production drilling and home stuff, mass spectrometer - hss is generally fine for most things people deal with. As soon as you move out of mild steel and harder youll need to take a closer lookhow about lubricants? what lubricants should be used for what drills? - depends but oil, kerosene, water based coolants generally fine. If carbide, you generally don't cool it as it can fracture the cutting edge.black oxide - probably can. But if you plan on cutting plastics, you dont want it as it provide a place for plastic to stickPolishing - most people don't polish, but it can probably help with material sticking in some cases

author: johansen
author_rank: Super Contributor
timestamp: April 27, 2016, 05:07:08 am
content: Quote from: sarepairman2 on April 27, 2016, 03:27:28 amdid you read what i said?the TIN coating on the end of the drill bit is not what does the work, the coating on the inside edge of the flute is where its needed.watch this video.

author: SeanB
author_rank: Super Contributor
timestamp: April 27, 2016, 05:11:55 am
content: Cheap drills ( any one sold at a box store or a hardware store, not a tool supplier) it does not make a difference, but if you buy good quality drills it does. I tend to buy HSS bits from the supplier down the road, unless I just want to drill a few holes and do not care about finish. I keep a set of good cobalt drills ( ground finish, with fullt sharpened flutes and a nice step) with each big tap and with the recoil kits, so that I can get a good hole each time. Might be $5 per bit, but worth it, as the hole it leaves is perfect.I did use a 3.2mm cobalt drill to do hand drilling, and it worked well till I broke it on the last hole, at an awkward angle where it slipped. Another time I was drilling out a lot of holes in 316l stainless steel, where it was all work hardened. I used one bit per hole as a budget. I bought 10 packs of 4.9mm HSS bits that day, made the salesmans day as I told him they would all be dead in the morning.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: April 29, 2016, 11:13:01 pm
content: The bottom edge is also involved, especially in manual operation: the relief controls the depth-of-cut. While it's not as important, it's not not important.I happened to see those Milwaukee bits the other day. They look like they have a higher twists per inch than a normal drill. This will increase the default rake (keener), making them hand drill steel a lot easier. The tip geometry looked OK too. The downside of the rake is that it makes the edge more fragile, and if you're using a fixture to sharpen them it'll have to be adjusted to accommodate the higher TPI.

author: Delta
author_rank: Super Contributor
timestamp: April 29, 2016, 11:24:20 pm
content: I've been unfortunate enough to have to drill out sheared stainless bolts (and also then stainless bolts with sheared easyouts made from about the hardest steel known to man stuck inside them), and the only bits that would cut it (shit pun intended!) were cobalt ones. About the only time I managed to persuade management to splash out on decent tools...

author: Paul Moir
author_rank: Frequent Contributor
timestamp: April 29, 2016, 11:42:05 pm
content: Yes, I have done this many times too. Easy-outs aren't.Since getting geared up with a TIG welder I haven't had to do it.

author: Ian.M
author_rank: Super Contributor
timestamp: April 30, 2016, 12:04:37 am
content: A sheered stainless bolt is a nightmare to drill out because the fracture line will be extremely work hardened. The other problem with threaded stainless components is that stainless on stainless galls very easily, and the sheered bolt is likely to have friction welded itself to the thread in the hole so the chances of an easyout shifting it aren't good. Stainless in Aluminium and similar light alloys is prone to electrolytic corrosion of the aluminium, which tends to build up enough lateral pressure to lock the bolt in the hole or even fracture the alloy round the hole if its near an edge. Once that happens, the chances of getting the bolt out and saving the thread in the aluminium are small - you'd better have a stainless helicoil kit handy, or you may even have to TIG it up and redrill/retap.

author: tautech
author_rank: Super Contributor
timestamp: April 30, 2016, 06:05:10 am
content: Quote from: Delta on April 29, 2016, 11:24:20 pmThat's really good to know, thanks for sharing.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: April 30, 2016, 06:29:49 am
content: Quote from: Ian.M on April 30, 2016, 12:04:37 amThis is where the TIG comes in. You start a puddle on the top of the sheared off fastener, and it rounds convex away from the aluminium sides. Then you just sit there, pouring on the heat for as long as you like which expands the aluminium. Then you put down some filler, making a nice ball. Then you weld it to a bit of scrap for a handle. Give the fastener a few seconds to cool, then start rocking it back and forth. If you get some movement, hit it with some tapping oil or penetrating oil or whatever and work the fastener out. If the handle breaks free of the fastener, try again.You can do this with any other process, but with MIG and stick the weld metal starts piling up quick when you're in the pouring-on-the-heat phase.Incidentally, for truly galled stainless fasteners (eg, stainless nut & bolt), if you have a little movement slowly work in some tapping fluid. I've had some pretty good success getting them apart that way. It must be the EP additives?

author: SeanB
author_rank: Super Contributor
timestamp: April 30, 2016, 07:18:32 am
content: I use the WAP gearbox oil as a nice EP cutting fliud. As it has so much EP additives it is almost oil free. Do not use it any more as the pump it was used in was "liberated" one night.For gearboxes a tube of Molyslip is a very good additive, as it makes them run a lot cooler. Helps if the lube is a 630 viscosity gear oil which always foams.I have a nice recoil collection, from M2 to M20, and a good number of US sizes as well for some stuff with US parts.

author: Marc M.
author_rank: Regular Contributor
timestamp: April 30, 2016, 08:11:30 am
content: If you're not in production or need to drill harder materials, don't waste your money on anything other than quality HSS 135* split-point drills and a can of proper cutting oil. Split point drills not only drill easier, they also have less of a tendency to walk when you're starting to drill your hole. If you need your hole location to be accurate, always center punch the location or better yet, use a spot drill if you're using a drill press, mill, etc.Using a proper cutting oil will reduce wear on your bit, improve hole accuracy, and make drilling faster and easier. For general purpose drilling/tapping in most metals other than aluminum, I prefer Relton Rapid Tap. When tapping larger stuff > 3/8" / M10, I prefer to use dark sulfur based cutting oils. For general drilling and machining of aluminum, WD40 works well, it's inexpensive, and easy to apply. When tapping aluminum I use Relton A9 specifically made for the task, but WD40 works in a pinch.Regarding Cobalt, here's a post from Forest Addy on the Practical Machinist forum regarding cobalt drills. Forest is one of the Grey Beards, Grey Beard over there and forgets more in a day than most will learn in a lifetime. In my book, he's the machinist's equivalent of Jim Williams."...Cobalt HSS drills are intended for stainless and hardened alloy steels where heat and abrasion are factors in the cutting environment. They feature “red hardness” and hold their edges when drilling the toughest materials. Cobalt HSS drills are intended for severe duty meaning they are made with thick webs and smaller gullets. Consequently, chip clearance will be more of a problem when using cobalt drills especially when drilling deeper holes. Unless you're drilling stainless, very hard bronzes, heat-treated alloy steels, or titanium alloys, so-called "cobalt" drills are overkill. Cobalt HSS offers no advantage in drilling wood, mild steel, and softer non-ferrous metals.There are some myths about cobalt drills. One may be attracted to the cobalt drills sold in sets at the big box stores; some with colorful coatings. The old set at home might be dull or it might be a cheap set purchased on impulse from an import seller. So you buy a set of cobalt drills for about triple the price of an equivalent quality HSS set. What kind of performance improvement can you expect?Of course new drills work great because they are fresh and sharp from the factory and there is the "placebo effect" associated with every new purchase. The thrill fades after some use and a few hasty free-hand sharpenings. In the end the new cobalt drills perform no better than your beater set. You spent the money and you got… what?Marketers are quick to pick up popular misconceptions and exploit them ruthlessly. Thus we see "cobalt" HSS drill sets at low-price importers. Whether they actually perform as well as an honestly presented cobalt bearing HSS alloy (M42 or equivalent) we have no way of determining by appearance alone. It's only when we get them to the shop and attempt to sharpen one can we tell by the sparks (sparse red-orange streamers) and abrasion resistance (high) if we bought the genuine article. For the unscrupulous importer “cobalt” drills are just one more gimmick to extract money from the naive home shop purchaser.It's the metallurgy that makes the difference in drill performance and while budget Asian import tooling is improving with time their metallurgy can be dubious. Therefore I strongly suggest you purchase your M42 drills from a quality supplier, not from knock-off sources - and then only the sizes you need if the purchase of a full set is not clearly indicated. Expect to pay $350+ for a real 115 pc cobalt drill set.Consider your workload. Make your purchase decision on the basis of your actual need and the materials you usually drill. The performance superiority of M42 cobalt HSS drills over M1 HSS in their recommended application is significant. If conventional HSS drills perform poorly in your particular line of work (stainless steel yacht hardware for example) then moving up to a cobalt bearing HSS drill may be a good idea. "----------------------------Carbide is by far the hardest of the bunch and will cut just about anything. This comes at a cost both monetarily and in durability. Because they are so hard, they are very brittle. Speeds, feeds, and the rigidity of the machine tool are critical to maximizing their life. I do use them on occasion in hand drill motors mostly for drilling out Socket Head Cap Screws that some ignorant gorilla over-tightened and stripped out the socket trying to remove them. More often than not, the drill doesn't survive intact, typically chipping the lips especially at the corners. I have never broken one in half (they won't take any amount of radial loading). As Paul mentioned, they are easily sharpened with silicon carbide or better yet diamond but a quality mask or respirator MUST be worn along with good ventilation as carbide dust is nasty stuff. Unless you have very specific needs and the correct equipment, stay away from carbide (outside of masonry bits).

author: SeanB
author_rank: Super Contributor
timestamp: April 30, 2016, 10:33:58 am
content: For screw removal I never will use the common tapered extractor, but instead I love a RIDGID fluted extractor set. Comes with the drills, the alignment collets ( bloody important) and the fluted rods and drive sleeves, in a nice plastic box. Drill the offending bolt or stud down the middle with the bit and a collet ( use a lot of cutting paste there) and then tap in the fluted rod, place the drive nut on it and turn it out.For stripped cap screw heads just set the fluted rod into it and turn it out, or drill down in the premade guide and turn it out.I have broken the smallest drive rod, and unfortunately RIDGID agents do not honour the lifetime warranty ( unlike Gedore and Snap on except for screwdrivers) so now I have 2 sets of them. Even though they are expensive, they are definitely worth it working on machinery.I buy shit tools at the hardware, but the good stuff comes from either Drakewoods ( down the road) or Toolquip, where you pay for the quality. Last purchase was the start on getting the full set of adjustable reamers, but just bought the 2 sizes I needed right then, $200 each. Whole set is ca $2000 for the dozen in a box. Made in Czech republic, and I did not have to remove the excess grinding paste from them when I got them and stripped and relubricated them. Not so with the PRC tools, I am still removing grinding paste from parts after 5 years of use, but I am getting good at stripping it apart for repairs.Soon will play with my new plasma cutter, going to beat using a grinder for sure. Next will be a TIG welder, even though most production welders use MIG for speed.

author: Corporate666
author_rank: Unknown
timestamp: May 01, 2016, 12:45:14 am
content: Cobalt bits are fine for handheld drills - it's carbide you don't want to use in a handheld drill. Cobalt is no problem at all.But in general, any shit drills you buy at a hardware store will be of such crap quality that I would never even think of getting coated drills there. Coating will help drill performance in extreme conditions when used right. But there is simply no possible way to "use the drill right" with a hand tool. It's not about technique either... you just simply don't have control of rigidity, feed, speed and lubricant like you do in a machine tool like a CNC machine.For 99% of people, even buying cobalt drills is likely a waste of time. Unless you are cutting something hard that HSS won't cut - some types of steel, for example. But for general use, if you're buying at the hardware store, just get the plain (bright) finish drills and forget about cobalt or shiny coatings. It will have absolutely zero effect other than to reduce the thickness of your wallet.Having said that, if you are careful with your tools and use them right, and if you drill things often or you just want good performance, skip everything at the hardware store and get a real set of drills from a good supplier. And if you're doing that, go for cobalt over HSS every time.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 01, 2016, 04:46:22 am
content: Heck, I've gotten the idea to replace the most important sizes with carbide tipped jobber bits. Something like $20 at McMaster, but should last about forever doing fiberglass (PCB stock), which is the most abrasive material I work with in terms of quantity.Tim

author: sarepairman2
author_rank: Frequent Contributor
timestamp: May 02, 2016, 12:11:58 am
content: Quote from: johansen on April 27, 2016, 05:07:08 amomg this is amazing

author: sarepairman2
author_rank: Frequent Contributor
timestamp: May 02, 2016, 12:14:45 am
content: Quote from: Delta on April 29, 2016, 11:24:20 pmlol management and decent tools