OT: 0.1mm flat screwdriver, any hint where to find it?

Hi

Sorry for the off-topic. I am doing a watch repair and need a 0.1mm flat screwdriver. Been searching the web for 1 hour and got no hits

Anyone been down that road?

Thanks

Klaus

Reply to
Klaus Kragelund
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Try searching for jeweller's screwdriver ?

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Reply to
TTman

I have. The smallest I have found is 0.5mm

Reply to
Klaus Kragelund

I have one of these:

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I think they are called sensor blade in english

I could cut the 0.1mm blade off, and try to use it as a screwdriver, but that just seems plain stupid

Reply to
Klaus Kragelund

that's a very narrow blade, maybe start with piece of 0.1mm spring steel wire and rub it on a sharpening stone to form a blade,

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  Jasen.
Reply to
Jasen Betts

Would grinding a .5 work ?

Reply to
RheillyPhoull

Not me, but flat screwdrivers are easy to make. You'll probably need to do that because a 0.1mm flat screwdriver is easily broken.

The smallest I could find is 0.5mm.

Start with whatever you have that looks like a jewelers screwdriver. Use a Dremel tool and an abrasive disk or mini grinding wheel to create the 0.1mm screwdriver tip. When making something that small and pointed, you're going to ruin the existing heat treating no matter how you do it and how you cool it. Heat the flat tip with a propane or MAPP gas torch until it's cherry red hot. Dump the screwdriver in oil or water as fast as possible. Test with a file. If a file skips over the surface, you've hardened it. Then, anneal it down to a brown or blue color. If you find that you can't harden it, it might be "mystery steel". Use a spark test to check if it's high carbon.

Something like this but with a much smaller screwdriver blade:

More details:

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Steel tempering color chart:

Tempering colors of steel:

Any help in tempering jeweling screw drivers?

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

flat blades are measured by width not thickness

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  Jasen.
Reply to
Jasen Betts

I have a 0.2x0.7. But I bought it in Tokyo at TokyoHands in Shinjuku.

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Perhaps buying one of this and sand it down?

But this shop offers one:

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...that is 0.5mm wide. So it is possible it is 0.1mm flat.

Olaf

Reply to
olaf

There's a watchmakers and micromechanics school in my city and I've bought some prototyping work as student work from there.

They learn to make their own tools before building watches - you've found one of the reasons why they do this!

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mikko
Reply to
Mikko OH2HVJ

How does anyone cut a thread on the screw that takes such a driver? And who makes the die?

And so ad infinitum...

Reply to
Mike Coon

That's about the width of a human hair. What screw is that small?

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Reply to
TTman

Feeler gauge.

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Reply to
Clive Arthur

Wow, it occurred to me, but I dismissed it, because how would you be able to purchase the correct screwdriver then? :-)

But, thanks, that probably solves my issue, so I can go ahead and order a 0.5mm one

Reply to
Klaus Kragelund

Great explanation, thanks :-)

I have a blow torch, - and did metal hardening back in school 30 years ago. So been a while. If I cannot find one that fits I will try your idea out

Spark testing, I didn't know such a test existed. Fun stuff

Reply to
Klaus Kragelund

Come to think of it, there is probably a standard for that, as there is for the thread dimensions:

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Reply to
Klaus Kragelund

No. Flathead, slotted, or minus sign screw drivers are measured by the width of the blade, not the thickness. Sometimes, you'll see a

2nd number after the blade width, which is the shaft length. Just to make life difficult, some larger slotted screwdrivers include whether the tip is flared (tapered), or parallel, which has more to do with the diameter of the grinding wheel used to grind the tip than any strength requirement. In general, 4mm or smaller slotted screwdriver tips are nearly parallel.

In the distant past, I worked for my father in his lingerie factory in Smog Angeles. During the 1960's, good screwdrivers were expensive. My father favored Craftsman because he could exchange them when I fumbled something and broke the tips. It was easy enough to regrind a slotted screwdriver or even a Philips driver. However, the tip would not last. If I wanted it to last, I had to heat treat (harden and anneal) the tip. Nobody cared what they looked like, so all the tips were always black from the used motor oil quenching[1]. Only the tips (about 5mm) needed to be heat treated. Eventually, tool manufacturers got the clue and started advertising drivers with blackened tips as a premium driver, for a premium price, of course. The problem was that few of them actually bothered to harden the tips. Proto Tools hardened them: but the other manufacturers simply plated or painted the tips black. For example: The same thing happened later when interchangeable tips became popular. The good tool manufacturers heat treated the entire driver, while the junk was just black paint:

Some basics in heat treating hand tools: "How To Heat Treat / Temper Hand Tools & More!" There's far more if you want to get into cryogenic heat treatment, which is what the high end knife makers use.

For a tiny 0.1mm, the heat treating is critical. Too soft, and the screwdriver will twist in the slot. Too hard, it will break. Properly hardened, it will have the strength, without also being brittle.

[1] Quenching should be in used, not new oil, so that it is full of carbon which provides a form of surface case hardening.
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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

I just took some pictures

Watch disassembled:

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Screw and 0.2mm sensor blade

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It's a little to wide to fit in the flat slot, so I figured I needed

0.1mm screwdriver

Picture of sensor blade:

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It's a citizen divers watch

Reply to
Klaus Kragelund

Sensor blade = feeler gauge in the US.

Oh-oh. The 0.1mm seems to be the width of the slot in the screw head, also known as the thickness of the screwdriver blade. This slot width is normally not specified. You don't need a 0.1mm wide screwdriver.

Googling a little, it looks like one of the Citizen divers watches is

43 mm diameter: Using the photo #1 to scale the watch diameter against the screw head diameter: 33mm screw_head * 43mm watch_diam / 720mm watch_diam = 1.97mm screw_head (The 33mm and 720mm are as measured on my computah monitor)

A 2mm screw head diameter is a much more reasonable screwdriver size for watch screw than 0.1mm.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

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