Sharpening drill bits by hand - Page 21


View Poll Results: Do you sharpen drill bits by hand on a bench or pedistal grinder?

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  • Yes I do it all the time!

    579 70.52%
  • No, they never cut right!

    45 5.48%
  • Sorry, I don't know how to do that!

    63 7.67%
  • Its better to throw them away!

    29 3.53%
  • No, we have a drill sharpening machine!

    91 11.08%
  • What's a drill bit?

    14 1.71%
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Thread: Sharpening drill bits by hand

  1. #241
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    Default

    When I was 25 I could sharpen .020 circuit board drills by hand on a diamond wheel pinching a 5x eye loupe in my eye socket, now at 51 I am lucky to be able to point a .125 diameter drill that way. I was so good at it I found it faster to pull a drill out and regrind it than walk to the tool crib or ask the supervisor for one. I am self employed so this is also a way to save money.



  2. #242
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    Default Re: Sharpening drill bits by hand

    I can do it, but get a drill doctor, it pays for itself. if u have to do it without a drill dr, just make sure the wheel is dressed nice, and even number of strokes on each side



  3. #243
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    Default Re: Sharpening drill bits by hand

    I bought a diamond grinding cup a few weeks ago with the intention of using it interchangeably on my 8" bench grinder when I wanted to sharpen carbide bits or tooling. Made an adapter collar (spacing out so the nut gripped it and fitting its 20mm internal bore on the 16mm spindle) and whacked it on. Ran pretty smooth and true, but because I work from the side of the grinder instead of the front with the cup, I need to make up a steady. Or some kind of compound slide so I can get a little more precise - I'll be happy when I can use it to grind single point threading tools out of stubs of carbide cutters

    Anyway, it was on there and I had to sharpen a 10mm HSS jobber so I grabbed any old bit of junk as a hand rest and touched it up. Ye gods, what a difference it made vs the 'fine' standard grey wheel on the grinder. Cut through 316 stainless like it was cheese, beautiful spirals of clean swarf.

    I may be placing myself here for a whole bunch of knowing looks and "good one numb nuts, everyone knows that" but, for any others like me that didn't: a diamond wheel does a much nicer job than the crappy standard grinder wheels. Thanks to fleaBay, it cost all of ten bucks too!



  4. #244
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    Default Re: Sharpening drill bits by hand

    A diamond wheel is not suitable for HSS cutters, only carbide.....CBN type for steel, and they ain't cheap.
    Ian..



  5. #245
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    Default Re: Sharpening drill bits by hand

    I have to agree that a diamond wheel should not be used on HSS, at least if there is any appreciable speed of that grinding wheel. As I understand it, the heat can literally cause the diamond to be eaten up, becoming carbon that bonds with the steel and you have less diamond on the wheel and a different steel alloy.

    But I am curious about two details. First, what grit was that wheel? I suspect the grit size is more responsible for your good results than the fact that it was diamond. And second, what was your source?



    Quote Originally Posted by dharmic View Post
    I bought a diamond grinding cup a few weeks ago with the intention of using it interchangeably on my 8" bench grinder when I wanted to sharpen carbide bits or tooling. Made an adapter collar (spacing out so the nut gripped it and fitting its 20mm internal bore on the 16mm spindle) and whacked it on. Ran pretty smooth and true, but because I work from the side of the grinder instead of the front with the cup, I need to make up a steady. Or some kind of compound slide so I can get a little more precise - I'll be happy when I can use it to grind single point threading tools out of stubs of carbide cutters

    Anyway, it was on there and I had to sharpen a 10mm HSS jobber so I grabbed any old bit of junk as a hand rest and touched it up. Ye gods, what a difference it made vs the 'fine' standard grey wheel on the grinder. Cut through 316 stainless like it was cheese, beautiful spirals of clean swarf.

    I may be placing myself here for a whole bunch of knowing looks and "good one numb nuts, everyone knows that" but, for any others like me that didn't: a diamond wheel does a much nicer job than the crappy standard grinder wheels. Thanks to fleaBay, it cost all of ten bucks too!




  6. #246
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    Default Re: Sharpening drill bits by hand

    Thanks guys, good to know. Every day here is a school day.

    And yes, ChipsNChips, quite possibly it was more about the grit size - the diamond wheel was 240 grit vs the 120 of the wheel.



  7. #247
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    Default Re: Sharpening drill bits by hand

    Hi, anytime you find a cheap source of CBN grinding products, especially cup wheels in the 125mm diam size.....post them here....I've only ever seen them at over a hundred bucks a piece.

    I have a Cuttermaster tool and cutter grinder and the instruction manual recommends using CBN wheels over aluminium oxide as the way to go......the big advantage is.....no grinding grit or risk of stone breakage from constant dressing etc.
    Ian.



  8. #248
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    Question Re: Sharpening drill bits by hand

    Dressing CBN wheels.

    Hi Ian.
    Some of your expertise please.
    I have a white soft stone like thing for dressing CBN. Actually rips out the CBN from the surface, I believe.
    White dressing stick wears REALLY quickly, but seems to work.

    I tried a diamond dresser. Haha. I just did a beautiful job dressing the diamond!!

    So, CBN wheels can be used to dress diamond dressers, it seems?
    At least I can use EDM to poke holes in carbide, with ease. Even cutting threads in it is possible, with CNC, but that is another story.

    Neil

    Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.


  9. #249
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    Default Re: Sharpening drill bits by hand

    Hi Neil......back in '75 a shop I worked in had an EDM carbide grinder......it looked like a diamond wheel but the disc was a brass type material that rotated fast and you had to earth the tool before pressing against the wheel.

    I've got the Fleming EDM construction book so one day I'll get down to building an EDM.

    I'm trying to get a 125mm CBN cup wheel for my cutter grinder.....relatively cheap etc......the ones on EBAY all say "CBN diamond wheel".......what that combo is I don't know.....I assumed it was one or the other, cost about $100.....diamond type are only $25.

    BTW......the wishbone type drill sharpener I showed you some years back has been working overtime and the flat diamond impregnated sharpener is still good to go.
    Ian.



  10. #250
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    Cool Re: Sharpening drill bits by hand

    I use my wishbone (from your drawing/picture) many times per week.
    Here are some links for others that are curious
    http://www.cnczone.com/forums/polls/...tml#post253413

    the picture I made mine from.
    http://www.cnczone.com/forums/polls/...tml#post452788

    my one..
    http://www.cnczone.com/forums/polls/...tml#post453542

    the cad files..
    http://www.cnczone.com/forums/polls/...tml#post453963

    I found the trick with small drills.. 0.4mm carbide, on a fine green grit wheel, (diamond dressed)
    1. holding the drill in the wishbone, and holding the drill bit with my fingers just grind the end of the broke drill square to the end.
    2. orient the drill so to line up desired cutting edge orientation with the wishbone rollers.
    3. Again holding the drill close to the tip, touch on grinding wheel and feel the temperature rise.
    4. Flip 180 degrees and do it again based on temperature rise.
    5. Inspect with a loupe, and touch up as required to be even.
    6. Finally lap using wishbone with it's rollers on a flat diamond lap or worse still, oilstone.
    I put a iece of tape on one side of the lap to run the roller along.

    With a bit of practice, takes about 1 minute, after you have broke the first few drills!! WEAR GLASSES!!
    A bit more practice and you can do 0.35mm ones, or 0.30mm.

    Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.


  11. #251
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    Default Re: Sharpening drill bits by hand

    Hi......I 've been using a 10X loupe to see the drill point detail, but last week I went onto EBAY and invested in a USB microscope.....$36....it's basically just a small 10 MP camera on a vertical spindle and base.

    The EBAY listing said it was a 60 to1000 X magnification, but when I measured 2 lines 1mm apart it only appeared to be 60 X at most on the monitor screen......if I saved the image as a Jpeg and then blew it up.....probably that's what they meant...... at 10MP the image should blow up quite a bit before pixelating.....the depth of field is quite good.

    My intention is to make an optical type projector/inspection device but with the camera actually seeing the object 3D as opposed to a shadow outline.

    I'm quite familiar with optical projectors and the need for parallel light rays for shadow graphs etc as I used one in industry for many years.

    It's early days yet, so some further design/research is needed.
    Ian.



  12. #252
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    Default Re: Sharpening drill bits by hand

    CBN cup wheels 125 mm dia - quite a few on eBay at $40 or less.
    You just have to tune your search a bit.

    The >$100 ones are 200 mm diameter and larger.

    Cheers
    Roger



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