Sharpening drill bits by hand - Page 3


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!

    608 71.03%
  • No, they never cut right!

    46 5.37%
  • Sorry, I don't know how to do that!

    63 7.36%
  • Its better to throw them away!

    30 3.50%
  • No, we have a drill sharpening machine!

    94 10.98%
  • What's a drill bit?

    15 1.75%
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Thread: Sharpening drill bits by hand

  1. #41
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    Quote Originally Posted by The Puma Man
    Just let me say, this is all bull+++t really. I've been a machinist for some 35 years and if a close tolerance is required you just can't rely on hand grinding, it's just not reliable. For open tolerance (0.3 mm) then yes maybe. Close tolerance work drill grinder every time
    Perhaps in the hands of some people a drill cannot be sharpened to cut within about 0.002" of size but it can be done. And when you are talking drilled holes with standard HSS bits anyone who thinks they are reliably getting much better than that even with a new drill is dreaming.

    Yes it takes time and a drill grinder is faster but it is possible; I was doing it about 44 years ago.



  2. #42

    Cool

    Quote Originally Posted by Geof
    Perhaps in the hands of some people a drill cannot be sharpened to cut within about 0.002" of size but it can be done. And when you are talking drilled holes with standard HSS bits anyone who thinks they are reliably getting much better than that even with a new drill is dreaming.

    Yes it takes time and a drill grinder is faster but it is possible; I was doing it about 44 years ago.

    Too bad you didn't work with me, I have sharpened .040 cobalt drills using a long slender stone under a microscope all day long, as they were getting .0002 tollerance in each 304-SS part the CNC's were drilling!

    I have stoned a slight radius on the outer points of hand sharpened drills and made them actually cut undersize!

    For twenty years, I wore an eye-loupe clipped on to my egeglass frame, as everyone would constantly ask me to sharpen their tools! Having a nice set of diamond plated files, and assorted stones in my toolbox, was a necessity in the places I'v worked!

    The hardest thing to sharpen is those damn one lip carbide engraving tools, as one slip and the point is toast!

    Eric



  3. #43
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    Quote Originally Posted by Geof
    Perhaps in the hands of some people a drill cannot be sharpened to cut within about 0.002" of size but it can be done. And when you are talking drilled holes with standard HSS bits anyone who thinks they are reliably getting much better than that even with a new drill is dreaming.

    Yes it takes time and a drill grinder is faster but it is possible; I was doing it about 44 years ago.
    So Geoff, you think you’re so clever. I can sharpen a drill in less than a minute using our drill grinders, unless it’s a big drill bit say 40 mm dia. and above, which takes possibly 2 minutes. Now I’m talking about repeatability and very quick turn around because in the airbus industry of which I work we cannot afford to have one, scrap, and two, unreliability and if you say you can grind 100 drills in say 2 hours’ by hand and they all cut size FIRST TIME, well I’ m thinking you must be Clark Kent



  4. #44
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    Quote Originally Posted by The Puma Man
    So Geoff, you think you’re so clever....
    Nope, check: http://www.cnczone.com/forums/showth...6&page=5&pp=15



  5. #45
    Registered tobyaxis's Avatar
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    Originally posted by The Puma Man (quoting didn't work)

    So Geoff, you think you’re so clever. I can sharpen a drill in less than a minute using our drill grinders, unless it’s a big drill bit say 40 mm dia. and above, which takes possibly 2 minutes. Now I’m talking about repeatability and very quick turn around because in the airbus industry of which I work we cannot afford to have one, scrap, and two, unreliability and if you say you can grind 100 drills in say 2 hours’ by hand and they all cut size FIRST TIME, well I’ m thinking you must be Clark Kent
    --------------------------------------------------------------------------



    Quote Originally Posted by Geof

    Geof is clever, wise, and cool

    I am Honored to be able to visit a place with members like him, Widgitmaster (Eric), LakeSide (Mike M), Tjones, Gandalf (Wolfgang), MetLHead (Scott), Ger21, Huflungdung, GenGuy, CarbideCraters, Miljnor and so many others. I've made a lot of good friends here.

    We come here to Help and be Helped, not to Knock eachother.

    And if I sound corny.......GOOD!!!!!!!

    Pumaman,

    Take it easy Dude!!!!!!!! This isn't a compitition!!!!!!!!

    Last edited by tobyaxis; 07-30-2006 at 07:36 PM.
    Toby D.
    "Imagination and Memory are but one thing, but for divers considerations have divers names"
    Schwarzwald

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

    www.refractotech.com


  6. #46

    Default

    Thanks tobyaxis!

    I Agree, the reason for this poll is to inform others, not to compete or compair!
    This fourm is superior in every way, and I will continue to share ideas, knowledge, and my experiences with others freely!

    In the past I have worked in shops where I felt a dumb as a box of rocks, and in other shops I felt superior and under paid! Everyone's knowledge level and skills are at different strengths, and it has been my experience that anyone can learn if the desire is present in both the apprentice and mentor! A good example was the massive factories during the wars, where everyday women were doing amazing jobs on machines and in foundries while their men were getting killed on the front lines!

    Well, the war is over, and we are now at peace !



  7. #47
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    Default Sharpener plans?

    I see this thread is a bit old, but here goes.

    My dad, a toolmaker, taught me to sharpen drills by hand about 50 years ago and it has served me well. I mostly use a drill doctor now but there are problems with it, like setting the original holding position as different web sizes produce vastly different results.
    Anyway I'm not interested in discussing Drill Doctor, but I am wondering if there are plans out there for a good quality, home built drill grinder. I'm a hobbiest machinist, so time is plentiful, money to buy a used grinder is not. (shipping et al)

    The cheapies, like Sears, seem to use the right principals, but lack any kind of weight or solidness. Would it make sense to use the geometries of those units to build a sturdy unit? But then they won't narrow, will they?

    Small bits are really cheap so there's no need for tiny sizes, but I might like to sharpen a 1-1/4" rather than pitch it.

    Thanks,
    Jerry



  8. #48
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    My apologies Geoff I thought you were knocking me in the answer you posted to me!!



  9. #49
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    Quote Originally Posted by ozzie34231
    Would it make sense to use the geometries of those units to build a sturdy unit? But then they won't narrow, will they?
    Small bits are really cheap so there's no need for tiny sizes, but I might like to sharpen a 1-1/4" rather than pitch it.
    Thanks,
    Jerry
    Why dont you try making one Jerry and post a build log so others can give info, suggestions etc etc. I cant try myself as I dont have the necessary eqpt yet.



  10. #50
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    i like to sharpen my bits i learned about 5 years ago from this 75 year old man i thought he was full of s%*t but i tried it and have done my bits ever since



  11. #51
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    Hi all, the question is how many drills and how often to sharpen. To sharpen and gullet a drill by hand is an aquired skill. I learned that over 40 years ago. If you just dont have the time to stop and sharpen then a dedicated drill sharpener is the way to go, but for the normal general everyday useage one of those gadgets that attach to a bench grinder work well. You can build your own as they're relatively simple.
    I sharpen 1/2mm drills with a small hand honing device on a diamond lap, and get accurate results every time with correct lip length and point angle. You can't even see the point of this size, so I use a 10 X jewellers loupe. I had to drill 316 stainless with a 1.2mm drill going through 7mm deep, and resharpened after each drilling.
    If anyone wants a design for drill sharpeners, from 1/2mm diam to 2" diam + that would take only a few hours to make and cost little, I'll supply a sketch.
    Ian.



  12. #52
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    Ian, is the design similar to the venerable "Potts" grinding jig? never got around to making it (learned how to do it by hand & have a T&C grinder now) but seeing competed ones it always seem a lot nicer that those $19.95 ones you buy.



  13. #53
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    Love to see the design!

    Jerry



  14. #54
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    Hi Mac, yes the Potts type is the principle involved. The design For this type came from the Model club I used to belong to some years back, and one of the guys drew up one and had it published in our club Magazine. He used his own interpretation and came up with a very simple but easy to make item. It required a metal plate under your bench grinder to make a firm base, and a bush attached to the plate so that the drill jig is firmly presented to the wheel. I've yet to make one as it does make drill ginding in sizes above 3mm easy and accurate. It wont handle small drills below 3mm, too fiddley due to the nature of the set up. I made the other drill honing thingy to do all those small drills down to .5mm when you can't even see the end of it.
    I'm about to build a small t&c grinder from bits and pieces I've got. Without one your stuffed when it comes to end mills and slot drills going blunt on you. The trouble with designing machinery is you get carried away with specifications that just seem to grow and grow untill in the end you've set the world on fire and never get to make it.

    Last edited by handlewanker; 09-15-2006 at 10:20 AM.


  15. #55
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    Hi all, when I learned the mystical manooverin' of the wrist and elbow that is required to sharpen a drill, commonly called "The drill sharpeners fandango", it wasn't at the "coal face" so to say. It was one afternoon with a 1" drill and a stationary grinder. Once you get the knack of the rotate twist and drop the end bit, it all comes easy. Then you switch the grinder on and mark the end of the drill with RED marker, and lightly do your thing. If you've got the hang of it, then just lightly touching the drill to the FRONT, not the side, never the side, anything but the side, you should see a light pattern of grinding marks across the whole of the cutting face as the grinding wheel touches the drill while you rotate it and drop the end a bit. It is of the utmost importance to say that the grinding wheel should be freshly dressed, otherwise you'll just get the worn face of the grinding wheel superimposed on the drill, and you can forget about gulleting a drill if the edge is rounded.
    The other point is when you present the drill to the wheel it should be above the centreline of the grinding wheel, about an inch above so that you get the back off angle at the start of the grind. The drill will be parrallel to the ground at this point. You MUST use a drill point angle gauge. If you dont have one, make one from a bit of sheet metal. Without it you just can't judge accurately enough the two angles. I've seen some people measure the lip length with a 6" ruler to judge centrality. The most accurate way is to lay the drill on it's side and rub the point against a vertical piece of chalked metal and see if the point is central. S'easy! The whole point of the exercise is skill. if you want to be recognised as a skilled craftman then know your stuff. Here's another one for another time, grinding a screw cutting tool bit for cutting left hand two start threads, internal. Really seperates the men from the boys allright.



  16. #56
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    Hi all, just been thinking about the problems with grinding drills when the existing grinder, with it's well used wheels between redresses, is the only one available. Buy another one, a real cheapie, hobby model, 6" double ender from the local home hardware supplier, $50 or so, Put a medium grit wheel on the left side and an aluminium oxide cup wheel on the right side, and only use it for doing the drills.
    The cup wheel with it's fine edge will make thinning the point so much easier, and it wont break the bank.



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    At my NTMA school, the first thing we do on the shop is they taught us how to grind down 1/2 x 1/2 x 2 inch steel into lathe toolbits which later on the training year we use them on the lathes to make our other projects. But current job I have right now, they use nothing but carbide inserts, which kinda sucks going through all that burning finger pain. But now when the time comes that the engineers summon me to make their part, I sometimes need to make a custom cutting tool, so all I do is get 1 carbide insert and grind the crap out of that instead



  18. #58
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    Default Drill Grinding

    I Was never "taught" drill grinding but given a very large box of very badly abused drills and shown a pedistal grinder, Some hours later i could grind a reasonable eadge to a drill and it would cut, Now i know engieers who have had many years experance who sadly ask me to regrind there drills.

    I would aggree that a minimum of 20% just can not and will never be able to regrind a drill.......split point well i can give it a go but i wont say it good..



  19. #59
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    Default Just do it

    I unlike most was taught machining from the ground floor. Vertical mills, lathes, grinding, heat treating, metalergy, etc... I think that the art of hand grinding drills and lathe tools is almost completly lost. I am 31, out of the last 10-12 guys I have hired ranging from 20-60 years old not 1 could hand grind a tool. Get out your machinery's handbook, a good pedestal grinder and take the time to learn. In my shop we often have to match up to glass threads, look in J&L and try to find a tool for that. Many times you can not take the time to order a special drill bit, end mill, or lathe bit, even if it does exist.
    THATS WHAT A GRINDER WAS MADE FOR.


    Excuse the grammer, I am better with handwheels and push buttons.



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    Default mcgyver reply

    I am looking for a Potts type grinding jig I see that you have made something similar would it be possible to pass some sort of drawing or plan on to me?



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