Trying to sharpen old hand drills

[Philipp Jaindl]

Good evening, I'm in need of some help.

I've been trying to sharpen up my great grandfathers hand drills after stumbling across them recently (without much success). They are what we would call a "Snail-drill" literally translated, like a Spoon Drill with a twist to it, which was the standard from for them around here. If they are properly sharp they work really rather well, would be quite handy for the occasional large conical hole.

So far i tried with (oblong Scythe) Stones and Files (since i dont have Slipstones i tried using the slim rounded end of the Stones meant for Scythes which didnt really work all too well) with the Files i can get a sharpish edge but nothing anywhere close to sharp enough to drill with, like cutting the endgrain when drilling through a board. Do some of you have any experience sharpening Tools similar to this or any idea how i might get them sharp again?

regards Philipp

PS heres a Picture of them.

[Jim Koepke]

Hi Philipp,

Those are also called gimlet bits by some folks.

For sharpening the starting threads a knife edge file works. At least it did on one of my refurbished gimlet bits.

For the snail slipstones are possibly the best tool. Absent being able to acquire a set of slipstones you may be able to work with wooden or even steel dowels with an abrasive paper held around them to sharpen the cutting edges of the snail.

Another helpful item might be a chain saw file. They are a fine grade round file without any taper.

jtk

[Philipp Jaindl]

thanks for the quick answer Jim, i actually did use a Chainsaw File to try and sharpen it, with a slipstone do you polish the whole inside or just the edge? so far as you can see i tried only putting an edge on it, not even entirely sure its at the right angle i tried matching the old one.

Another thing, sharpening the outside to keep the diameter constant is a no-brainer but do you debur the outside or just leave as is and let it break off on the first hole?


Good to know they are called Gimlet Bits, wasnt sure on the English term.

[Jim Koepke]

The leading edge, the one doing the cutting when the bit is turning in the wood, needs to be sharp. As much as possible try to keep the original angle. Debur the outside but do not remove anything but the bur.

This type of bit will tend to cut a rough hole as compared to a sharp auger bit.

jtk

[Tom Bender]

Traditionally these would have been used in green wood. It cuts like butter. You may not have good results with dried hardwood no matter how sharp.

[Charles Guest]

Good evening, I'm in need of some help.

I've been trying to sharpen up my great grandfathers hand drills after stumbling across them recently (without much success). They are what we would call a "Snail-drill" literally translated, like a Spoon Drill with a twist to it, which was the standard from for them around here. If they are properly sharp they work really rather well, would be quite handy for the occasional large conical hole.

So far i tried with (oblong Scythe) Stones and Files (since i dont have Slipstones i tried using the slim rounded end of the Stones meant for Scythes which didnt really work all too well) with the Files i can get a sharpish edge but nothing anywhere close to sharp enough to drill with, like cutting the endgrain when drilling through a board. Do some of you have any experience sharpening Tools similar to this or any idea how i might get them sharp again?

regards Philipp

PS heres a Picture of them.

Drill several blind holes in a thick piece of wood (use a hardwood), the diameter should be smaller than the gimlet. Pour emery powder into each hole, put a drop or two of machine oil on top of the emery in the filled hole. Then, drill all the way through with the gimlet, or at least to the gimlet's working depth. Do this until they're pretty clean. You'll ruin them with stones and files. The ones you have look pretty pitted. They'll never be perfect but they won't cut at all if you ruin the geometry. It might help if you treat them in rust remover first. Evaporust seems to do a pretty good job.