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Thread: Drill sharpener

  1. #1
    Join Date
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    Default Drill sharpener

    Gentlemen,

    This subject has probably been done to death.

    I recently had to drill two holes acturately on a centre pop mark, through 12mm ms.
    Hole No.1 was 6mm, hole No.2 had to be 6.4mm. The holes were drilled in a mini mill.

    The 6mm drill was made by Suttons, the 6.4mm drill was made by P&N.

    Both drills were new, and had been sharpened in different ways. Suttons had a single relieved cutting edge on each side, P&N had two. The normal one, then a secondary greater relief.

    This is what I found. The Suttons drill wondered off centre, the P&N was spot on.

    Why is this so?

    Secondly, who makes a good quality, low cost, drill sharpening holder? I have had a bit of a squize on this forum, and most of the replies are for sharpening drills by hand.

    I would like to able to machine sharpen drills, so I know they are shmacko, spot on.

    Any comments will appreciated.

    Regards,

    Ken

  2. #2
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    Default

    Drill Doctor, expensive though. I can sharper a bit well enough to drill a hole, but if I want, say, a 13.5mm hole using a 13.5mm bit, and not 13.55mm hole, then the DD makes up for my sharpening deficiencies.

  3. #3
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    Blue Mountains NSW Australia
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    Sharpen them by hand.

    If you want them all spot on.... practice practice pratice and then practice some more.

  4. #4
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    All my good drills, endmills & slot drills go to Auswide Saw & Tool at Burleigh heads for sharpening.

    The so-so drills, I sharpen on one of them things that attach to a lecy drill.

    A pro re-sharpen is a joy to behold. 10mm,16mm & 20mm carbide 6 flute endmills are better than new.
    Hooroo.
    Regards, Trevor
    Grafton

  5. #5
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    Perth WA
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    The reason is that the flat section between the two flutes of the standard grind Sutton drill is wider than the centre pop mark. The P&N has a sharper point so was able to stay in the centre pop mark.
    In both cases to make sure I would have used a centre drill or at least a stubbie 1/8th dril as a pilot before using the larger drill.
    Cheers,
    Rod

  6. #6
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    Aug 2004
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    Perth WA
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    I've got an adjustable drill sharpening guide/holder that sits to the side of a bench grinder so that it uses the side of the grinding wheel. Igot it a few years ago from Carbatec to which I just had a look on their site but couldn't find it.

  7. #7
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    Default Drill sharpening

    Ken,
    I am the king of klutz, ham fisted and etc etc.
    However I can sharpen drills by hand because I know I can, and therefore I am able do it.

    I was taught by a young maintenance fitter who showed me the basic hold and manipulation of the drill bit whilst it was being ground.

    The whole exercise centers around partial rotation of the drill shank and dipping the end at the same time to gain the necessary clearance.

    To gain an idea of drill clearance think of your drill cutting edges as two inclined but sharp rotating cutting edges.
    The only points of cutting contact are at these edges.This only occurs on a correctly sharpened drill bit.The clearance is the space ground back so the remaining section of the drill lobe doesn't rub and cause friction,heat and burn out. It gives the chip somewhere to go.
    There is a bit of judgment needed for getting the cutting edge angles the same.That comes with practice.

    One of our members posted a terrific set of graphics quite recently on how to hold and grind a drill by hand.

    Sure you might mess up a few drill bits in learning but this will be off set by the future savings over a drill sharpening machine and buying new drills.

    Slip down to the markets and buy some second hand drill bits if $ are a problem. You can do it .Confidence will come with practice.

    If I can do anyone can.
    regards
    Grahame

  8. #8
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    Hi Grahame & others,

    Thanks for all your comments.

    How about I put the drill up in my mini lathe chuck and grind the end to get the right angle with a tool post grinder. Once done, remove the drill bit and hand grind the relief.

    Is this cheating?

    Regards,

    Ken

  9. #9
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    Hi Ken,
    Very good advice from Graham...

    If it were me, I wouldn't think it would be worth the setup time. When you get good at it, drill sharpening becomes second nature. I always select a bit and then usually walk over to the grinder to sharpen as a matter of course. It is such an easy thing to sharpen bits when you develop the skill. That is why I advise to practice. and develop the skill. My father in Law is a toolmaker, and that is how he learn't. He would say..... the boss used to grind down several bits at the close of work each day, and get him to shrpen them. He said it took him six months to get the skill to satisfy his boss. I am very much better and far superior to my father in law, in so many ways. It didn't take me long to get the hang of it. Anyway, I have had more than a few wines this evening so I better let go now.

    To answer your question Ken, just have another correctly ground bit handy to use as visual refernece when gring by hand.

  10. #10
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    Dodgy brother

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    Sounds like the P & N bit was sharpened with what is called a split point, as you mentioned a greater secondary relief angle. Supposed to provide better centring without walking across the workpiece.


    The beatings will continue until morale improves.

  11. #11
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    Drill Doctor is the only answer for those of us not fortunate enough to have done a hands on engineering apprentership.

    Yep, expensive, but IMHO the best way to go for those that just want superb results with little understanding about angles\cos\tan etc...

  12. #12
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    Fossil,

    Steve, I'll have a go at sharpening by hand.

    I'm catching up to you with the glasses of "medicine". Maybe a couple more will give me the needed confidence.

    Ken

  13. #13
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    Default

    Quote Originally Posted by PPW View Post
    Drill Doctor is the only answer for those of us not fortunate enough to have done a hands on engineering apprentership.
    ppW

    What a load of -Whoops,I nearly answered that in my boilermakers mode.-I'll revert to the profesional teacher level.
    Ahem!

    Yes I had a hands on apprenticeship,but did not do any drill sharpening-Crikey in those days of demarcation,Boilermakers did the boilermaking and Fitters sharpened drills. Three or four years into teaching I did a night course in lathe operation at Tafe and picked it up the skill over two or three nights.

    Its a mental attitude thing ppW .You tell yourself you can't do something and sure enough you will not be successful.

    Once you practice and have a bit of success,you find you want to improve and you do bit by bit,that is drill bit by drill bit.
    I have taught a couple of interested kids at school how to sharpen.They picked it up fairly quickly.It is a matter of wanting to.

    Have a go! You have nothing to lose but your blunt drills.

    Grahame

  14. #14
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    Default Past post on drill sharpening

    Guys
    heres some good oil from a couple of years back.

    http://www.woodworkforums.ubeaut.com...t=23003&page=2

    Grahame

  15. #15
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    It is common how many tradesman don't know how to sharpen a drill even roughfly.
    I was watching an aleged roof plumber erecting an awning at my house when I saw him trying all these different drills and breaking some.
    I asked him what was the problem . He said , "nothing I just have run out of drills . I will have to go down the street and buy some".
    I was looking in his tool box and he must have had 20 drills of the same size . I said, " Why dont you sharpen them? He said , " I don't know how " So I took them down to my shed and sharpened them roughfly as they were only being used on less than precision work .
    It is the same thing with young carpenters , few know how to sharpen a chisel or plane blade , because they don't use them much anymore.
    He was amazed and said can you show me how to do it ? So later I did.
    My hand grind style is a bit different to Grahames . I hold the drill at the required point angle and grind until I get full cut along the edge and then tilt the end of the drill in toward the wheel and draw the back of the drill angle up the wheel to create a relief behind the cutting edge . Repeat for other side periodically applying an angle gauge to the two edges . You have to play around with one side or the other until the point angle is good and both edges are sharpe with back relief. I move to the edge of the grinding wheel to draw it up to get the back relief on big drills . I dont think I rotate it .
    The thing is that drilling deep holes that have to be straight it is vital that both drill point cutting edges cut the same so the drill does not wander off. For this class of work a drill sharpening jig should be used or professional sharpening to get precise point geometry.
    I personally would not grind HSS in my lathe but if you do make sure you cover as much of the bed and saddle as possible with good " safe " covers that will not get caught up in the spinning work. Then clean the lathe afterwards.

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