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Machinists: critique my twist drill sharpening.

6876 Views 65 Replies 23 Participants Last post by  fj40guy
Ok, I've read and heard about those expensive, fancy, store bought drill sharpeners. Drill Doctor is about the cheapest little thing you can buy. You can get crazy with a CNC twist drill sharpener that will run you $18,000 and cut a twist drill into a miniature mouse dildo.

BTW, we're in the metal shop, so these are not 'drill bits'. You gotta go next door to 'The New Yankee Workshop' to find those. Here in cutting oil land we call them twist drills. Don't ask me why, it's just what I read. :confused:

So, being a poor man, and hearing that 'old machinists' could sharpen twist drills on their own, in their sleep, I was of course intrigued.

Newer twist drills have a 'split point' edge. In order to sharpen them using this method, you have to 'thin the web' I don't have this problem since I have the cheapest bits around, so I don't have anything to critique there. I could figure it out I bet.

I put the grinder rest at an angle I figured was conservative.

I measured the cut angle by placing a large bit on the face of the stone and marking the shank resting on the guide with a sharpie. :rolleyes: Only the most precise methods for me!

I eyeballed the edge to get it centered, and I think I did pretty good. The picture I took was with one hand holding it 18" from my body. With two hands it doesn't walk at all. Using a center punch it doesn't walk either of course, and the hole's not egg shaped.

It's not the 'sharpest' thing around, but I drilled 7 or 8 holes, and had no dulling I could tell.

This is the drill I used as a guide:


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Brandon said:
I love my DD, and if ya go to drilldoctor.com and enter RCRCi as the code you save 25% ;)


I just read the whole thread, very cool to do it on a grinder - I sure as hell can't. I'll keep my crutch ;)

Looks like you beat me to posting the 25% deal, so I won't post my review and discount code :)
jerseyzuks said:
I use both. I find the Drill Doctor works better on smaller bits (1/8" & 5/32" etc), but the grinder works better for larger bits. I have the basic DD model (the $80 one?), and it won't accept really large bits, so I must sharpen those by hand.
I wasn't aware that DDs have a web thinning (split point) option too. That's nice. I'm a machinist and have always ground my drills by hand at home or on a Christion or Condor grinder at work. For me it was just pratical to pay $29 for a bech grind as opposed to $100+ for a DD, BUT the web thinning option changes things. For all the [email protected] we throw at our grinders web thinning on them is tough, the wheel corners are never sharp enough or you need to dress the h3ll out of it to get a sharp corner. Even then I find the wheels are too coarse to keep a sharp corner.
Because I never thinned webs for home drills I have always kept a decent set of center drills, eliminating the need for split points, at home anyways.
I wasn't already natural for me to hand grind I'd be all over a DD.

MC, there's another really nice carbide tipped drill, Lexington makes them. I can't hold the .0005" tol with them but I'll rough 1.0" holes in 101Cu all week long with the same drill, 2-3 diameters deep. They'll hold + or - .002" easily.
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Pavemen said:
Looks like you beat me to posting the 25% deal, so I won't post my review and discount code :)

go for it, I don't get anything for using that code so the more reports to read the better. I am sure I could find it from your sig ;)
What the heck, here is my review

Discount code is PSCOMi for 25% off at drilldoctor.com and there is also a $10 mail-in rebate at the bottom of the page.
I've posted up about my Dad sharpening drill bits before. He was good!

Our grinder was a hand operated one. String attached to a foot pedal, and you took a little bit to get that grinder up to speed with the rythm of your foot. He would hold his drills by hand, and just rest them at the right angle while spinning them to a razor sharp tip that would go though metal like butter. Never learned how he did it! :(

BellaVista... yes, when he worked at Lockheed (1930's/1940's) he had a HAND DRILL for working on prototypes. Hollow drill handle, that held about 10 bits. He had a habit of sharp tips up, dull ones down. Come to think of it, he did the same in his tool box drawer.

Still amazing to think of all those holes and rivets being done by HAND!

DD for me. :)

Tom :usa:
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