I just got a Brownell's Thin-bit screwdriver set. They are very thin, but not thin enough for some screws on my Grulla or my Lebeau. I am aware that they can be ground thinner, but does anyone know of a set for sale anywhere that has thinner bits than those? The thinnest ones in the set are .020"
TIA. Joe

Joe, I doubt that you can find anything thinner than .020". You may as well resign yourself to grinding. Some gunmakers seem to take pride is seeing how narrow they can make their screw-slots. Makes one want to strangle them.
nial

You might try a set of watch repairer's screwdrivers. They can be picked up quite cheaply. The set of 8 that I have go from 2mm. to 0.7mm. Lagopus.....

Hello Lagopus,

I believe they are talking thin, not narrow.

JC

I have the Wheeler Engineerng 72 pc set and am more than happy with the different selection of widths and thicknesses.
From what I have read about the European guns is that the screws are thinner in the slot area than most of the American guns.
I have recently acquired a Greener circa 1892 and wanted to look inside to inspect everything. Found the bits that fit the narrow slots and could not break some of the larger bottom reciever screws loose. So left them alone.
I don't know what they used to do the job, but ater this many years it is possible that moisture worked it's way to the threads. Might need some pentetrating oil and try again.

Lads, whenever I need a certain sized driver I consider it expendable and grind it to fit the slots. German guns have notoriously thin slots so I might use the driver only once. A better way of going about it is to buy oil hardening drill rod (Cheap from Enco.com) and form your own bits with the belt sander or Dremel Moto-Tool. Heat treat them once ground to proper shape by heating cherry red with a propane torch and quenching in any kind of oil (I use drain oil from my car). Draw the temper to a straw color or light brown, requench and you are set. Keep a bunch of such bits near your drill press where you can chuck them up and hand turn the subject screw out by using the quill feed. A cheap, easy way to make a bunch of unique bits. Chopperlump

Brownells sells a little grinding wheel that fits in the drill or drill press. They are extremely easy to use at slow speeds and will do the job you want.

Lenard

You will have to grind them. I just purchased some buffalo horn turnscrews and had the fitted to the individual screw.

I thought that you might be after some smaller drivers for inside the locks. Lagopus.....

Brownell's sells, or used to sell, a set specifically designed for the A-5, along with the caveat that they weren't warrantied against breakage. Some of the A-5's I've had apart leaned toward very thin slots. You might try a set.
Jim

Probably the most tedious, but a method to obtain the strongest thin driver would be to forge the tip down as far as practicable, then grind, and heat treat. A simple and available material to wor k with is 4130 steel. You can simply heat cherry red and quench in oil and you're done, no tempering needed for these thin drivers.

Thanks, all, for the answers. I also have a regular Brownell's Magna-tip set with plenty of extra bits so I guess I'll just gringd down one of those. Any suggestions on what diameter grinding wheel to use to maintain the hollow ground shape?
TIA! Joe

I bought a full set of the Brownells Magnatip's as well as the extra thin set. Rather than grinding the bits I use a very, very fine file, this then does not affect the temper of the steel,and is significantly more controllable. I just mount the bits in a vice and file very slowly to fit the appropriate screws.

The bits are also cheap enough if you break one. I definitely wouldn't use a grinding wheel, as in inexperienced hands they destroy the temper and can burn the steel and yiou then end up having to harden the steel which is just more hastle. The bits are aleady hardened to the best degree by the manufacturer.

Depending on how much needs to be removed, I would use a Dremel tool and go slowly before finishing with a file.

I'm a little surprised that the "thin bit" set didn't go thin enough but I haven't been buying new guns.

"I'm a little surprised that the "thin bit" set didn't go thin enough but I haven't been buying new guns."

Thanks guys. Montana, the Grulla that they don't fit is only 5 years old, but the Lebeau was made in 1975! European guns seem to have REALLY thin screws.
Joe

I forgot to add that I cheat too. When I had the opportunity I had Nick Makinson make me a secondary lockpin for my 1909 Grant with a more bulbous head and a slightly wider slot...

Montana, is that the one with the side lever?

JC

The thinnest bit in the Brownell A-5 set measures .020"... (Jim, they are still available - at least as of six months or so ago.)

Yep. Starting to get so I can shoot it...

Buy the wheel that Brownells has listed for sharpening/thinning the their bits. It is meant to be run at slow speeds and there is no chance of over heating the metal. Plus it is so easy, even a cave man could do it.

Lenard

Thanks, Lenard, I saw that in their catalog and I think I'll buy it.
Joe