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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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The cutting edge (in blue in the picture) should be higher than the trailing edge (in red). I can't tell from your picture if you ground it this way. I bought a Drill Doctor Journeyman 400 and it is well worth the money. I use it all the time.


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