I'm learning to hand-sharpen Drill bits

Bob Korves said:
With a split point you do not need a pilot hole as long as the work is perpendicular to the drill and the surface is reasonably smooth. Saves time, more accurate holes.
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But there's also so much torque that without a tommy bar, the taper comes lose from the tail stock and/or the jacobs taper breaks free of the drill chuck. Still, maybe I can do things differently now. I just figure that if there's that much resistance, the pilot serves a good use. I never considered that it may be less accurate, but If I'm drilling that large, I"m probably going to bore it out anyway. Something to remember though.
 
I have had enough trouble with step drilling big holes on the lathe that I have taken to just drilling with the biggest drill I know I can safely run in one shot, and then boring it the rest of the way. Slower, but safer, and tooling and machine parts don't take the chance of getting damaged, sometimes badly. I decided to quit tickling that tiger while I was ahead of the game. One "OH, ****!" cancels out dozens of "atta' boy's".
 
MikeWi said:
....trimmed....
Doing this by hand goes against all of my OCD needless-precision instincts. I want jigs and such to ensure perfect results and repeatability, but dang, this ain't bad at all. :)
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I like that phrase... also enjoyed the article you shared.
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If only I had 'the touch' then maybe I'd succeed at freehand sharpening. Just have to keep practicing I suppose.
 
Doubleeboy said:
the trouble with doing a pilot hole is the finish size drill gets its outer cutting edge beat to death. One drill and then bore for me.
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It really depends on the ratio of the pilot to finish size. If the finish size is only cutting on the outer edge then I agree with you. If the cutting edges of the drill are being more fully utilized then this is not a problem.
 
Ok, it took a while to wrap my head around how to grind the back to get the split point, but I think I succeeded pretty well. While I was at it, I added the two outside facets as well on my test bit, but I think I'll skip it in the future since that 140 degree point leaves a blind hole that's nearly flat if you don't add them. I drilled into the face of some 1" nominal HW store steel, and went an inch deep easily. It's a 15/16" bit for this test and you can just make out that the hole is off center, but the outside wasn't trued up anyway. Hole is .94 instead of .93, but I didn't check the actual drill width now that I think of it. All in all no where close to a scientific test, but I'm happy.
 
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