OldTools Archive
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260044 | Roy <rp77469@c...> | 2016‑09‑19 | How do you sharpen Yankee drill bits?? |
GGG, Tonight at our monthly Hand Tool gathering, a splinter group of the Houston Woodworkers Club. we hit a stone wall. Someone wanted to know how to sharpen Yankee drill bits. Even Mr. Leonard Lee's fine book did not cover this. Previous searches on the internet had found no instructions. I volunteered to post here as certainly one of the galoots must know how to do this. We tried sharping tips, we tried sharpening the bit by registering on the flute, we tried holding our tongues on both sides of our mouth, but nothing worked (although I still think we got a bit of improvement when the tongue was on the right side). Any tips, references, etc greatly appreciated. Thanks, Roy Parker |
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260045 | Joshua Clark <jclark@h...> | 2016‑09‑19 | Re: How do you sharpen Yankee drill bits?? |
I've looked for period instructions on how to sharpen these and came up empty in the past. I'd be curious to know if anyone can dig anything up. Lacking any concrete evidence, I looked at the NOS bits I have and found that they appear to be simply ground across the flute at an obtuse angle, maybe 135 degrees. I've done the same with my bits and it works well. They are simple tools and pretty hard to screw up. Josh |
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260046 | Kirk Eppler <eppler.kirk@g...> | 2016‑09‑19 | Re: How do you sharpen Yankee drill bits?? |
On Sunday, September 18, 2016, Roy |
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260047 | Charlie Driggs <cdinde@v...> | 2016‑09‑19 | Re: How do you sharpen Yankee drill bits?? |
Kirk, As I'm having difficulty visualizing the stone needed and then angle of approach (which may be due to being in wake up mode). Being so kind s to post a quick photo or two would be helpful. Those of us with an affliction for these drills could all benefit. Charlie Driggs Sent from my iPhone |
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260048 | Erik Levin | 2016‑09‑19 | Re: How do you sharpen Yankee drill bits?? |
Simply, they get sharpened pretty much like a twist drill. They cutting is primarily on the push stroke, so similar clearance angle is appropriate. You don't want too much clearance, or there isn't support, and the bit will push through the material, giving a poor hole and jamming up. You need some or the bit will rub rather than cut. It isn't critical. I have factory grinds from the 1980's and (roughly) the 1930's, and they are different, but not much. The 1980's had the grind done as a flat at an angle to give the appropriate cutting edge (roughly 120 to 130 degrees-- it isn't consistent) and a bit of clearance -- maybe 10 degrees at the cutting edge, but less farther back, making the cutting edge on the push a bit ahead of the trailing edge. The older bits have roughly the same edges, but the bits were rotated do the clearance is cut like it should be on a twist drill. I generally sharpen like the 1980's edition, as it is easy and works just as well. I don't worry about the details, only that there is a bit of a net clearance angle so the cutting occurs on the push, not the return. No jigs, just me and my fine wheel on the grinder, or a stone, or whatever. And, for the smaller ones, magnification. If the cutting edges are at substantially the same angle and same width, they are fine. *** This message was sent from a convenience email service, and the reply address(es) may not match the originating address |
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260049 | "yorkshireman@y..." <yorkshireman@y...> | 2016‑09‑19 | Re: How do you sharpen Yankee drill bits?? |
Fascinating question for those of us with bits needing fettling. how about drilling a bit size hole in a scrap offcut at the correct grinding angle - then just insert bit - register it using the notch, and rub back and forth on the stone? It’s hard to maintain an angle for something that small. Same idea - different set up to provide registration on a hand crank, if you want to salvage a broken bit. Richard Wilson Yorkshireman Galoot retired in Northumberland |
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260050 | Roy <rp77469@c...> | 2016‑09‑19 | Re: How do you sharpen Yankee drill bits?? |
On Sun, 18 Sep 2016 20:36:56 -0700, Kirk Eppler wrote: > I think I found directions somewhere on this list, years ago. Will take >some poking to refind them, if they weren't a figment of my imagination. > Should have thought of the archive right off the bat. Did a quick search last night and found 289 references. Will take a while to wade through all that, but the answer is likely in there somewhere. Thanks for the pointer. Roy Parker |
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260052 | Kirk Eppler <eppler.kirk@g...> | 2016‑09‑19 | Re: How do you sharpen Yankee drill bits?? |
On Sun, Sep 18, 2016 at 8:36 PM, Kirk Eppler |
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