Gimlet bits

[Michael Ray Smith]

I've picked up a few gimlet brace bits lately. Interestingly looking bits, but I don't know anything about them. (The only gimlets I know anything about have gin in them.) Does anyone know what they are used for?

[Andrew Kertesz]

You can google it and get a lot of info. In general they are used for making pilot holes for screws.

[David Weaver]

There are a lot of different styles of cutting ends on them, they're maybe similar, but people had different takes on them, I guess.

They're just used for drilling holes like anything else, but they are a bit more maneuverable. Maybe they were cheaper to make 150 years ago vs. a long auger bit.

You might find them useful for something, and you might not. If they are dull but not damaged, you can sharpen them, but care to not do more than just dressing the edges (from the inside) is important because you don't want to cut the outside of the flute inwards. I've had a lot of luck dressing the inside of the cutting edges on them with a worn 1200 grit belt on a belt grinder.

[Michael Ray Smith]

Thanks. I Googled it and, as you said, found that they're used mostly for pilot holes (I gather because they're tapered at the tip). I also found someone who said they work well for through holes because they leave a nice clean exit without the need for backing. I tried it, and that's right -- they do. I've only picked up 3, and unfortunately 2 of them are dull as can be. They look difficult to sharpen, especially the small ones. Looks like I'll need a small round file.

They're sort of interesting because there's a cutting edge on the side of the bit, so they cut wood from the side of the hole, not just at the bottom.

[Kees Heiden]

Larry Williams raves about them for drilling the mortice in moulding planes. They are easier to keep straight in the cut. Because they do indeed cut on the side they are not deflected so easilly by the varying grain in the wood.

[David Weaver]

They do work well for that. a cordless drill, some visual marking lines on a plane and a little care makes drilling the mortise holes a lot faster, though. That video caused me to buy a bunch of gimlets, but I generally use a cordless drill and brad point bit instead - (to me) it's important to be able to use a cordless drill instead of a jigged drill press just so you can easily maneuver the drill and keep it from wandering.

So for the folks who want to make planes and who can't find a good fresh gimlet, don't fret it. Trust your hands with a cordless drill, and mark yourself some visual cues for the direction the mortise needs to go on the sides and toe of the plane blank (you're going to have to do that to cut the mouth and lay out the mortise, anyway)

[John McPhail]

I have actually been imagining some type of jig to keep the drill from wandering. I'd been planing on using brace and bit, although I recently acquired a few gimlet brace bits I'd like to explore as well.

[Jessica Pierce-LaRose]

Given that it seemed Larry's preference for the gimlet was it's ability to "steer" a bit because of the cutting action, I wondered if one of those tapered bits, like are used as the center part of one of those all in one pilot hole-countersink bits would work well?

[David Weaver]

A jig won't keep a bit from wandering. If it's a tight tolerance jig that doesn't give you leeway to compensate, then a drill bit can drift all over the place. You only need your hands and feedback to tell you whether or not the drill is wandering and what to do with it.

plane totes have a much longer length drilled in them. For a while, I fought with bits and jigs, and other such things to try to limit wandering in macassar ebony. The best thing I've found to drill holes in them is some visual references and a cordless drill, with holes drilled freehand from both ends until they meet in the middle. The bit doesn't have to be much larger than the rod to do this successfully.

I always found the hole at the bottom of the tote to be way off with a long bit and a drill press and machinist-type vise stuff robbed temporarily from a buddy to drill a hole.

I don't know how many totes I've made since using a cordless drill to drill the holes, but maybe 10 or a dozen? I've never had to toss one though I had to throw away a bunch due to wandering drill bits with a tight setup.

[John McPhail]

David is there something about the cordless-ness of the drill that is crucial to you?

I totally understand visual references, I know how powerful they are when I use them to my advantage when chopping mortises.

[David Weaver]

Anything that isn't a drill press that you can maneuver around is fine.

[Bob Strawn]

A jig won't keep a bit from wandering. If it's a tight tolerance jig that doesn't give you leeway to compensate, then a drill bit can drift all over the place. You only need your hands and feedback to tell you whether or not the drill is wandering and what to do with it.

plane totes have a much longer length drilled in them. For a while, I fought with bits and jigs, and other such things to try to limit wandering in macassar ebony. The best thing I've found to drill holes in them is some visual references and a cordless drill, with holes drilled freehand from both ends until they meet in the middle. The bit doesn't have to be much larger than the rod to do this successfully.

I always found the hole at the bottom of the tote to be way off with a long bit and a drill press and machinist-type vise stuff robbed temporarily from a buddy to drill a hole.

I don't know how many totes I've made since using a cordless drill to drill the holes, but maybe 10 or a dozen? I've never had to toss one though I had to throw away a bunch due to wandering drill bits with a tight setup.

A shell auger is the answer to machine straight holes.


http://toolmakingart.com/images/Shell%20Auger/03%20Shell%20auger%20point.JPG

Easy to make a simple one like this, but it must be removed quite often to clear the chips. More details on it are in my blog entry on making octagonal handles. (http://toolmakingart.com/2011/02/27/how-to-make-an-octagonal-handle-shell-auger-and-straight-drilling-guide/)

There are shell augers that can cut deeper without having to be removed, but they usually cannot take a lot of sharpening and still have to be removed very frequently unless you have compressed air or oil being pumped through a hole in the drill bit to clear out chips. As far as simple, precise and easy to sharpen, I think this is the best profile for the small shop.

As far as gimlet's go, apart from the cleaner exit hole, a bird cage awl will beat a gimlet every time.

Bob

[Jim Koepke]

Looks like I'll need a small round file.

You might try looking at chain saw files. They are often less expensive from a logging supply store. We have a few of them around here.

jtk

[John McPhail]

Is a shell auger steerable?

[Bob Strawn]

Is a shell auger steerable?

Just the opposite. It has no side cut to it and this version is typically more of a face scraper. Grain has very little effect on it. It will pretty much go in the direction that it was started. Some people use a steerable bit on a hand held tool to compensate for issues and still make a straight line. If you are going to try and mount a bit in a handle, you can either make the hole with a long side cutting bit so you can see and tweak the angle, or you can use a shell auger. I have tried both, and use both, but prefer the shell auger when it is an option.

You can get a shell auger made for wood lathes. Look up lamp auger. The problem with them is that they can't survive a lot of sharpening and the sizes are extremely limited. If you have tons of money and room for a rather large and somewhat specialized metal working lathe, there are a lot of different gundrills that will do the same thing for you.

Bob