Russian screwdrivers....

[uhoh7]

So I have my 1958 jupi-9 and a great tutorial on how to get the helical clean, but my JIS screw driver is too wide for outer ring screws.

WHen I look up watchmakers screwdrivers they have sizes like .9 .6 etc

Any idea which one to get?

TY

Charlie

[peterqd]

I dismantled and reassembled my J9 OK using a 1.2mm blade. Not sure what you mean by .6 and .9 but if that's millimetres then I would think they're too small.

[Lightshow]

I use a cheap jeweler screwdriver and file it to the size I need.

[ForenSeil]

Be carfeul when filing a screwdriver. Use a lot of water etc. to keep the metal cool. I tried to file a screwdriver once but the metal got extremly soft (i guess through heating) and the screwdriver got unusable after 2 screws. But it was a very cheap screwdriver.

I got a very tiny screwdriver from an optician in my city for less than 3€.

[Lloydy]

Screwdrivers need to be hard on the surface to help prevent wear, but softer underneath to provide strength.

A good screwdriver, of any size, will be surface hardened, and that hardening will to be a very small depth. It will be microns on a small screwdriver. Filing the screwdriver to fit will remove the hard surface.

If they were hard right through they would be brittle and break, many cheap ones suffer from breaking because the hardening is too deep. Go the other way and the screwdriver bends through too little, or no, hardening.

Buy the best you can, it's worth every penny. The guy who repairs my watches for me buys a set a year, there's about 8 screwdivers in a set and they cost him about £150. But he never breaks one.

I avoid the cheap Chinese ones that you see in markets like the plague, but you can get decent hobby quality ones from a tool shop or engineering supplier.

[Jesito]

[iangreenhalgh1]

I hate to think how many cheap mini screwdrivers I've destroyed over the years!