Drilling brass - where do I purchase the drill bits?

Discussion in 'Clock Repair' started by NEW65, Jan 7, 2020.

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  1. NEW65

    NEW65 Registered User

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    Hi. I will be ordering from Mark B soon especially now I have sorted out payment methods :)
    However, we all know that drilling brass with ordinary drill bits isn't a great idea! I know that ordinary drill bits can be filed to make them okay to use in brass, but I have never done this before and would sooner just buy the right bits for the job.
    Any ideas? Did a quick search but they don't seem too popular.
    Cheers
     
  2. glenhead

    glenhead Registered User
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    I have never seen a set that's sold for brass or other grabby non-ferrous metals such as aluminum. (Maybe I haven't looked hard enough.) I bet if you could find a set it would be cripplingly expensive.

    I had the same concerns you did and finally just bought a pack of three inexpensive bits at the hardware store to dub, although ahead of time I called it "destroy". The process is really straightforward, just a kiss with a stone, and after you've done one you'll see that it's not as terrifying as it seems. It's also really effective, which makes it all the more satisfying. I tried one of the new bits, saw that yes, it grabbed, dubbed it, and smiled. I soon bought a complete drill index to dedicate to brass and dubbed them all. (Well, actually first I swapped out the un-dubbed ones for the ones I'd dubbed in the index I already had, but...) Here's an earlier thread where we discussed the process:

    Drill bits modified for brass ?

    Hope this helps.
    Glen
     
  3. bruce linde

    bruce linde Technical Admin
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    clickspring shows how to file drill bits for brass in one of his videos... go to his youtube page and do a search...
     
  4. bangster

    bangster Moderator
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  5. Willie X

    Willie X Registered User

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    All you do is decrease the cutting angle to verticle, or close to it. It's easy with drills over about 3/16" (use a .025" dremel cut-off disc). Under about 3/16" use the 'slips' commonly used to sharpen fish hooks. I have also used a small diamond file. You only meed to remove a tiny amount of metal. It's easy to resharpen and start over, if you want to try another angle. Willie X
     
  6. kinsler33

    kinsler33 Registered User

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    I have a fine diamond file (Timesavers, and Harbor Freight sells some) that I've used to brassify HSS (high-speed steel) drill bits. It takes only a single stroke, parallel to the axis of the drill, on each of the two cutting edges, to do it. Power tools aren't necessary. An oilstone would also do the job, and probably any sort of abrasive buff made of abrasive paper glued to a wooden stick would work as well. The difference is quite amazing, and I think you can still use the drill bit for steel.
     
  7. glenhead

    glenhead Registered User
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    Yes, you can use a dubbed bit for steel, but it will be really inefficient. To dub a bit you take the sharp corner off of the leading edge of the cutting surface. That corner is what lifts the peeled steel up and away from the bottom of the hole; it is also what causes the bit to dig in and grab brass. If the lift-and-separate isn't there for steel you're more scraping the bottom of the hole. That very quickly dulls the cutting edge while simultaneously burnishing and work-hardening the steel at the bottom of the hole. Double-plus ungoodness results.

    Glen
     
  8. NEW65

    NEW65 Registered User

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    #8 NEW65, Jan 8, 2020
    Last edited: Jan 8, 2020
    Big thanks to you all for informing me about adapting an ordinary drill bit to use in brass. I watched the video with interest too although as far as I remember it didn’t show a close up of exactly where to file the edge.
    I think I know now though but I don’t know why but I’ve had it in my head that taking a bit of metal off no matter how fine, will alter the diameter of the drill bit?! It’s probably a silly question but I’ve never really checked this job out yet! I really need to review it more closely. thanks as always
     
  9. gmorse

    gmorse Registered User
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    Hi NEW65,

    The part you're removing by stoning or filing along the axis is altering the rake of the cutting edge of the drill, and that won't alter the diameter of the hole it will make.

    Regards,

    Graham
     
  10. kinsler33

    kinsler33 Registered User

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    Whoops. Thanks for this: I was clearly misguided and should never have suggested that bits ground for brass would work properly with steel.

    I think I must have been impressed with myself for figuring out how to do the grinding myself. I should have known better, because I've never had any luck in sharpening twist drills. I even tried the Drill Doctor once and couldn't get it to work right.
     
  11. glenhead

    glenhead Registered User
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    If you slow the video down to 1/2 or 1/4 speed you'll see which what goes where. (I like how Chris more appropriately calls the sharpened edge the "cutting lip".) Pay particular attention to the following time marks in the video:
    0:56 - Holding the bit horizontal and parallel to the top surface of the stone. Note that at the tip of the bit the cutting lip is flat on the top of the stone.
    0:58 - An end-on view of holding the bit. Note that Chris holds the back end of the bit away from the stone in order to get the entire lip flat on the stone. Great shot there.
    1:00 - Chris emphasizes that this is a gentle procedure, and he's right. It takes surprisingly little force and just a few strokes to flatten the cutting lip.
    1:04 - The first shot of the results. Note the shiny flat at the edge and how it catches the light. That's what you're shooting for.
    1:10 to 1:19 - Chris rotates the bit to show both dubbed edges. I believe I remember that he said the amount removed isn't critical. It's also not critical that both flats be precisely the same, although the closer the better.

    If you go to your friendly neighborhood big-box hardware ("home improvement") store and get a couple of 1/8" drill bits (a 12-pack of them is less than $5) you can experiment and learn without breaking the bank. Also, it's not critical that you use a stone for this. I find it easiest, because the stone is a consistent and stable platform. 150- or 200-grit sandpaper on the edge of a ruler or something, a file, whatever you have that will cut/grind off the cutting lip will be peachy. Finally, regarding the concern about changing the diameter, a drill bit does all its cutting inside the outer edges of the tip. The whole outside surface of the bit is just a housing for the flutes to help raise the cut metal out of the hole. You're changing the attack angle of the cutting surface, not the outer circumference of the bit. If you went bonkers and started grinding off the outside then that would be a Bad Thing, but otherwise it's copacetic.

    This is one of those things that makes a huge difference in how things work. It's odd that we all have to kind of trip across it. Fortunately, it really is that simple. :)

    Glen
     
  12. glenhead

    glenhead Registered User
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    Yeah, sharpening drill bits. Ahem. :rolleyes: I've watched a whole bunch of videos on how to do that, and invariably end up going and buying a new bit. Sigh. That's one of those things I'm going to learn when I retire. Buy another 12-pack of 1/8" bits and see how many I turn into pivot stock before I get it right.

    Glen
     
  13. Willie X

    Willie X Registered User

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    You can re-sharpen a twist drill bit probably 50 times. On some the flutes are the same all the way up. On most, the core of the bit gets bigger as you go upward. This will stop you from doing a good resharpen about half way up. However that center can be thinned as you go. Just depends on your determination and your sharpening technique. Willie X
     
  14. Jerry Kieffer

    Jerry Kieffer Registered User
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    While there are drills specifically designed for all materials in industry including brass production, but they are certainly not purposely modified to be less efficient as commonly suggested in the home shop community. All quality drills are designed to cut metals as efficient as possible, with general purpose drills designed for all materials that can be drilled except hard steels in most cases.
    All drills are designed to be utilized in a way that a consistent controlled feed rate will not produce a overload and damage the drill and work piece. In addition ,the drill is designed to be utilized where it is mechanically controlled from pulling itself into a work piece again causing damage to either the drill or work piece.

    If one purchases equipment or uses procedures when drilling where a drill is not utilized as designed and you have issues, its not the drills fault. The common non industry suggestion when a drill takes a deep cut in brass is to stone the tip in a way that decreases efficiency so it will not take a deep cut. In reality, it is a method of attempting to resolve an issue that was purposely created in the first place by equipment or procedure.

    As an example, if your drilling on a lathe and you are using a lever tailstock, you do not have a way to control a feed rate other than hope for the best. In addition, you cannot react quick enough to control a drill that suddenly takes a deep cut.

    However, if your Tailstock is leadscrew controlled, then both feed rate and mechanical depth control are greatly increased and will control the drill in a way it was designed to be utilized..

    The question is, do you make it a practice of resolving issues you create or attempt to avoid creating issues in the first place.

    Just another point of view.

    Jerry Kieffer
     
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  15. kinsler33

    kinsler33 Registered User

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    But we don't do very much work with twist drills in brass when we're repairing clocks. If we were manufacturing bathtub faucets we'd be greatly concerned with the efficiency of the bits, and we'd make sure our toolmaker ground them to suit.

    I haven't any idea where you'd buy a twist drill ground for brass except for the ones that Mr Butterworth sells for use with his Butterbearings, and I've noticed that those are ground precisely as specified earlier in this thread. Timesavers, for example, doesn't list brass drills, nor does eBay. And while McMaster-Carr lists some, it's not clear that their cutting edges are any different from conventional twist drills: McMaster-Carr.

    But Harbor Freight Tools sells a competent set of high-speed steel twist drills (SAE only, unfortunately) for a few dollars. I've diamond-filed these for brass use and marked them with red nail polish, and I expect that they'll work nicely for the duration of my career, which thus far has averaged less than one hole in a brass clock plate per week.
     
  16. shutterbug

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    Drilling by hand is what gets folks in trouble. Jerry is a machine oriented kind of guy. Many here are in the "just get 'er done" thought process, and some get hurt, perhaps seriously, when a drill bit grabs their hand held piece of brass, yanks it out of their control and whacks them a few times before they can stop it. That's where altering bits is a better option than hurting yourself. Safety, like other things, is a lesson often learned the hard way.
     
  17. Jerry Kieffer

    Jerry Kieffer Registered User
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    Mark and Shutterbug

    You actually bring up a good point regarding free hand drilling.

    However, it is still not the drill itself that is the issue, but the procedure and the equipment. There is actually no issue in drilling a hole itself with a sharp unmodified drill. The problem is when high pressure is applied to the tip of the drill, it will break through the material as it exits and attempt to shear the remaining material, causing a sharp heavy twisting action on a hand held devise. This is actually more dangerous when drilling steel.

    Actually drills made in China and India from Harbor Freight and other such courses, can in part be part of ones solution. When compared to quality drills they rarely cut anything thus no safety issues.
    Again however, you do have to be very careful. Occasionally one will have a hard tip that may drill once or twice, but still no issue. The rest of the drill will likely be soft and simply unwind giving you a cushion and time to jump back out harms way. First attached photo.

    If a lesson is learned after the first issue and safety is a concern, I would suggest an accessory handle sold for all drills that allows one to more easily and safely control torque situations. Second Photo
    If this is still a concern, I would suggest a drill with an adjustable clutch that can be adjusted to ones physical strength when controlling torque. Third Photo.

    Jerry Kieffer

    fullsizeoutput_4c8.jpeg fullsizeoutput_4c6.jpeg fullsizeoutput_4cb.jpeg
     
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  18. Kevin W.

    Kevin W. Registered User
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    I learned long ago, clamp your work down.
     
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  19. kinsler33

    kinsler33 Registered User

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    Yes. I've had several disasters involving brass and twist drills. Oddly enough there doesn't seem to be much of a problem with small holes, say 1/16", even with an un-altered bit. The major trouble there, especially if you're making a deep hole, is that the bit clogs with chips every couple of seconds.

    I've been using Harbor Freight's drill bits for the last 20 years or more. There are some thoroughly horrible bits out there, but HF's bits don't unwind and even their cheapest sets have lasted me for years.
     
  20. Allan Wolff

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    Step drills, or unibits, work great for drilling brass; especially brass sheet which twist drills love to grab and fling about. Step drills have one cutting edge and work the same way as our bushing reamers and are capable of drilling an accurate size hole. I used to laugh at these bits as garbage, but a good quality step drill works great on brass. I have had good luck with Drill Hog and they have metric bits that will drill the correct size for Butterbearings.
     
  21. shutterbug

    shutterbug Moderator
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    You can get a step drill from Butterworths Clocks too.
     
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  22. NEW65

    NEW65 Registered User

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    Big thanks to everyone - I’m going to have a go tomorrow morning and report back on here. Glenhead thanks for explaining clearly how to do this. I did check out the video at the time intervals you mentioned and did see clearly what was going on. Thanks for that:)
    I do lots of rebushing and need different size drill bits for brass. I know that perhaps most you chaps don’t use drill bits when rebushing but the method that I use is very quick and accurate, giving great results every time. Mark B has a good variety of drill bits for using in brass and I will keep buying the range of sizes that you has available. Also he has a good range of bushings too. However now I know that I can convert ordinary drill bits I can now include other sizes that mark doesn’t have, to match the external diameter of the bushings. That’s why I prefer to use Bergeon bushings.
    I’ll come back on here soon.
    Thanks again everyone- you are all so helpful.
     
  23. bangster

    bangster Moderator
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    Never modify a regular twist drill when you can buy an expensive specialty drill for twice the price. :D
     
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  24. NEW65

    NEW65 Registered User

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    Nice one Bang :)

    I noticed earlier today that Mark B’s 2 mm bushings fit more snug in the plates than Bergeon’s 2mm bushings when using the same 2mm drill bit! Very odd. This shows that Bergeon bushings must be a fraction less than 2mm in diameter!
     
  25. Willie X

    Willie X Registered User

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    If you do "lots of rebushing", I would recomend that you skip all the guesswork, trials and errors and just buy a #3 KWM cutter. This tool is designed to do this job.

    Eventually you will need to buy a #2 and a #4 cutter but the #3 will do all of your American clock work and most of the rest. The #2 is used on cuckoos and the upper French pivots. The #4 is used on larger (usually German) clocks. Any drill press (with a very low speed) and you're good to go. Next on your list would be a bushing tool or a mini mill ... Willie X
     
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  26. Jerry Kieffer

    Jerry Kieffer Registered User
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    Hey Bangster
    If you were to pay twice for a drill than you normally pay, you will quickly learn you have been taken to the cleaners. Quality costs many times more than that.

    Jerry Kieffer
     
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  27. kinsler33

    kinsler33 Registered User

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    There seem to be good Chinese drill bits--after all, the Chinese build all of our consumer goods, presumably with Chinese-made tooling--but I'm privileged to have a selection of small American-made number drills that my father snagged when Koller Hardware in downtown Cleveland went out of business in maybe the 1960's. Most were made locally, by the Cleveland Twist Drill Company or by The Standard Tool Company, also of Cleveland. They've been marvelous pivot drills, including the #75 (from Standard) that I used to repivot an anniversary clock escape wheel. (Yes, I had to increase the pivot size.) My home town was and perhaps is the tooling capital of industry and still makes specialty steels and secret cutters.

    One of my clock customers here in Lancaster, however, runs a tool-sharpening business. Not for kitchen knives, but the cutters critical for special metalworking processes. His shop is equipped with a shadowgraph machine and such, and the FedEx and UPS trucks have to negotiate this miserable hill he lives on, for his customers are located all over the world. I have no idea why he was hesitant to work on his own undistinguished Emperor kit grandfather clock.

    Oh: my tiny antique Cleveland drills came mostly in envelopes, but the very smallest were packaged in tubes made of either cardboard or wood.
     
  28. Kevin W.

    Kevin W. Registered User
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    We have a cnc drill grinding machine at work, it makes drills from drill blanks. I dont know the smallest size it can do, perhaps around 1 eighth. What is the smallest they do in the drill sharpening place Kinsler?
     
  29. kinsler33

    kinsler33 Registered User

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    I doubt that the fellow I referred to does twist drills, and he seems to work exclusively with industrial customers. Your cnc drill grinder sounds fascinating.

    The smallest drill in the number series is the #80, which has a diameter of 0.0135 inches, which comes out to 0.343 mm. I imagine that watchmakers use smaller ones, and cannot imagine how you'd sharpen (or even manufacture) a twist drill that small.

    Old story, probably an urban legend: technical institute 1, wishing to demonstrate superiority, sends a piece of world's thinnest precision-ground steel rod to technical institute 2.

    Technical institute 2 returns it with instructions for it to be microscopically examined. Technical institute 1 does so and thus discovers the hole that has been drilled through it.
     
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  30. Old Rivers

    Old Rivers Registered User
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    Mark,

    Cool story, read about it here:

    About Us

    Jerry Kieffer speaks highly of this company.

    Bill
     
  31. gmorse

    gmorse Registered User
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    Hi Mark,

    I don't know about other folks, but I don't use twist drills that small, I use spade, straight flute or 'D' drills; they're easier to make! Busch make good twist drills down to 0.5 mm, but smaller than that, I make them as I need them.

    Regards,

    Graham
     
  32. glenhead

    glenhead Registered User
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    My smallest spade bit is 0.004", or 0.102mm. The biggest one is a #52, 0.048" or 1.22mm. I've made a couple through the years, but to save time I bought the complete set of the ones available from Timesavers. I've been amazed at what a good job they do, no matter the metal.

    Glen
     
  33. shutterbug

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    Yeah, they seem to be able to cut through even hardened steel.
     

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