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

[Klaus Kragelund]

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

 

[Jeff Liebermann]

On Sat, 28 Nov 2020 00:09:02 +0100, Klaus Kragelund
<klauskvik@hotmail.com> wrote:

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?

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.
<https://www.esslinger.com/search.php?search_query=0.1mm%20flat%20screwdriver&section=product>

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.
<https://en.wikipedia.org/wiki/Spark_testing>

Something like this but with a much smaller screwdriver blade:
<https://www.instructables.com/Hardening-and-Tempering-a-Screw-Driver-softening/>

More details:
<https://www.google.com/search?q=hardening+screwdriver+tip>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Fri, 27 Nov 2020 17:30:45 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:

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.

Steel tempering color chart:
<https://www.engineeringtoolbox.com/tempering-colors-steel-d_1530.html>

Tempering colors of steel:
<https://en.wikipedia.org/wiki/Tempering_(metallurgy)#/media/File:Tempering_standards_used_in_blacksmithing.JPG>

Any help in tempering jeweling screw drivers?
<https://mb.nawcc.org/threads/any-help-in-tempering-jeweling-screw-drivers.128120/>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jasen Betts]

On 2020-11-28, Klaus Kragelund <klauskvik@hotmail.com> wrote:

On 28-11-2020 00:09, Klaus Kragelund wrote:
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

I have one of these:

https://www.elfadistrelec.no/no/folerblad-rustfritt-stal-mm-bernstein-515/p/18075835

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

flat blades are measured by width not thickness

--
Jasen.

 

[olaf]

Klaus Kragelund <klauskvik@hotmail.com> wrote:

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

I have. The smallest I have found is 0.5mm

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

https://shop.vessel-europe.com/de/product/251389

Perhaps buying one of this and sand it down?

But this shop offers one:

https://www.e-dohrmann.de/werkzeuge/uhrmacher-werkzeug/schraubendreher-05-bis-25-mm.html

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

Olaf

 

[Mikko OH2HVJ]

Klaus Kragelund <klauskvik@hotmail.com> writes:

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?

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!
--
mikko

 

[Mike Coon]

In article <rps0ub$11ss$1@gioia.aioe.org>, klauskvik@hotmail.com says...

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

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

And so ad infinitum...

 

[TTman]

On 27/11/2020 23:09, Klaus Kragelund wrote:

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

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[Clive Arthur]

On 28/11/2020 00:00, Klaus Kragelund wrote:

On 28-11-2020 00:09, Klaus Kragelund wrote:
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

I have one of these:

https://www.elfadistrelec.no/no/folerblad-rustfritt-stal-mm-bernstein-515/p/18075835


I think they are called sensor blade in english

Feeler gauge.

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

--
C

 

[Klaus Kragelund]

On 28-11-2020 07:05, olaf wrote:

Klaus Kragelund <klauskvik@hotmail.com> wrote:

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

I have. The smallest I have found is 0.5mm

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

https://shop.vessel-europe.com/de/product/251389

Perhaps buying one of this and sand it down?

But this shop offers one:

https://www.e-dohrmann.de/werkzeuge/uhrmacher-werkzeug/schraubendreher-05-bis-25-mm.html

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

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

 

[Klaus Kragelund]

On 28-11-2020 02:30, Jeff Liebermann wrote:

On Sat, 28 Nov 2020 00:09:02 +0100, Klaus Kragelund
klauskvik@hotmail.com> wrote:

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?

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.
https://www.esslinger.com/search.php?search_query=0.1mm%20flat%20screwdriver&section=product

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.
https://en.wikipedia.org/wiki/Spark_testing

Something like this but with a much smaller screwdriver blade:
https://www.instructables.com/Hardening-and-Tempering-a-Screw-Driver-softening/

More details:
https://www.google.com/search?q=hardening+screwdriver+tip


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

 

[Klaus Kragelund]

On 28-11-2020 11:43, Klaus Kragelund wrote:

On 28-11-2020 07:05, olaf wrote:
Klaus Kragelund <klauskvik@hotmail.com> wrote:

  >>> 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

  >I have. The smallest I have found is 0.5mm

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

https://shop.vessel-europe.com/de/product/251389

Perhaps buying one of this and sand it down?

But this shop offers one:

https://www.e-dohrmann.de/werkzeuge/uhrmacher-werkzeug/schraubendreher-05-bis-25-mm.html


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


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

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

https://en.wikipedia.org/wiki/ISO_metric_screw_thread

 

[amdx]

On 11/27/2020 6:11 PM, RheillyPhoull wrote:

On 28/11/2020 8:00 am, Klaus Kragelund wrote:
On 28-11-2020 00:09, Klaus Kragelund wrote:
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

I have one of these:

https://www.elfadistrelec.no/no/folerblad-rustfritt-stal-mm-bernstein-515/p/18075835


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

Would grinding a .5 work ?

Are we really talking about a screwdriver blade that is 0.004\" wide?

Doesn\'t seem right.

                       Mikek


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[Jeff Liebermann]

On Sat, 28 Nov 2020 08:55:48 -0000, Mike Coon
<gravity@mjcoon.plus.com> wrote:

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

Small screw threads are rolled, not cut. Actually, just about all
commodity screws are rolled, not cut. Trying to cut threads into a
thin rod puts a radial stress on the bolt which will then break, bend
or deform the rod. Rolling does a better job of supporting the bolt
and work hardening the threads.

\"Why are Rolled Threads Stronger?\"
<https://www.youtube.com/watch?v=4YfQHJ4n6s8>

\"The smallest screw in the world\"
<https://www.youtube.com/watch?v=NerJ2yiT3xw>
<http://piepklein.blogspot.com/2012/01/begin-van-een-moertje.html>
<http://1.bp.blogspot.com/-xtsww5ydKIA/TvDsaQIJ2CI/AAAAAAAAATQ/zo-01jDGFa4/s1600/0135.jpg>
0.1mm dia. 0.25 um pitch (about 1000 tpi).

>And so ad infinitum...

Yep. Usenet discussions never end.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[amdx]

On 11/28/2020 11:45 AM, Jeff Liebermann wrote:

On Sat, 28 Nov 2020 08:55:48 -0000, Mike Coon
gravity@mjcoon.plus.com> wrote:

How does anyone cut a thread on the screw that takes such a driver? And
who makes the die?
Small screw threads are rolled, not cut. Actually, just about all
commodity screws are rolled, not cut. Trying to cut threads into a
thin rod puts a radial stress on the bolt which will then break, bend
or deform the rod. Rolling does a better job of supporting the bolt
and work hardening the threads.

\"Why are Rolled Threads Stronger?\"
https://www.youtube.com/watch?v=4YfQHJ4n6s8

\"The smallest screw in the world\"
https://www.youtube.com/watch?v=NerJ2yiT3xw

 This one touted as the smallest screw in the world, still has a head
that is 0.012\" wide, so the 0.004\" wide screwdriver is to small.

Now, are we talk about the tip thickness?

                       Mikek

http://piepklein.blogspot.com/2012/01/begin-van-een-moertje.html
http://1.bp.blogspot.com/-xtsww5ydKIA/TvDsaQIJ2CI/AAAAAAAAATQ/zo-01jDGFa4/s1600/0135.jpg
0.1mm dia. 0.25 um pitch (about 1000 tpi).

And so ad infinitum...
Yep. Usenet discussions never end.

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[Jeff Liebermann]

On Sat, 28 Nov 2020 12:10:32 -0600, amdx <amdx@knology.net> wrote:

\"The smallest screw in the world\"
https://www.youtube.com/watch?v=NerJ2yiT3xw

 This one touted as the smallest screw in the world, still has a head
that is 0.012\" wide, so the 0.004\" wide screwdriver is to small.

Now, are we talk about the tip thickness?

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:
<https://www.google.com/search?q=proto+screwdrivers+black+tips&tbm=isch>
but the other manufacturers simply plated or painted the tips black.
For example:
<https://i.imgur.com/zXgVIZ3.jpg>
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:
<https://www.youtube.com/watch?v=0_pB2R9KNzg>
<https://www.youtube.com/watch?v=Y7RSfVqbjSo>

Some basics in heat treating hand tools:
\"How To Heat Treat / Temper Hand Tools & More!\"
<https://www.youtube.com/watch?v=I9lgwNp7v0E>
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.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[amdx]

On 11/28/2020 1:49 PM, Jeff Liebermann wrote:

On Sat, 28 Nov 2020 12:10:32 -0600, amdx <amdx@knology.net> wrote:

\"The smallest screw in the world\"
https://www.youtube.com/watch?v=NerJ2yiT3xw
 This one touted as the smallest screw in the world, still has a head
that is 0.012\" wide, so the 0.004\" wide screwdriver is to small.

Now, are we talk about the tip thickness?
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:
https://www.google.com/search?q=proto+screwdrivers+black+tips&tbm=isch
but the other manufacturers simply plated or painted the tips black.
For example:
https://i.imgur.com/zXgVIZ3.jpg
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:
https://www.youtube.com/watch?v=0_pB2R9KNzg
https://www.youtube.com/watch?v=Y7RSfVqbjSo

Some basics in heat treating hand tools:
\"How To Heat Treat / Temper Hand Tools & More!\"
https://www.youtube.com/watch?v=I9lgwNp7v0E
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.

 I didn\'t get my point across. You posted what was supposed to be the
smallest screw in the world.

It had a a head the was 0.3mm across. Why would you need a screwdriver
that is 0.1mm wide for that screw.

I think that would be a bad choice, It seems to me a screw driver 0.3mm,
or 0.25mm  wide would be better.

Does Klaus have a screw that is smaller than the worlds smallest screw?
OK being a little factitious there.

Klaus, how wide is the slot on the end of the screw you are working on?

                                             Mikek


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[Klaus Kragelund]

On 28-11-2020 22:27, amdx wrote:

On 11/28/2020 1:49 PM, Jeff Liebermann wrote:
On Sat, 28 Nov 2020 12:10:32 -0600, amdx <amdx@knology.net> wrote:

\"The smallest screw in the world\"
https://www.youtube.com/watch?v=NerJ2yiT3xw
  This one touted as the smallest screw in the world, still has a head
that is 0.012\" wide, so the 0.004\" wide screwdriver is to small.

Now, are we talk about the tip thickness?
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:
https://www.google.com/search?q=proto+screwdrivers+black+tips&tbm=isch
but the other manufacturers simply plated or painted the tips black.
For example:
https://i.imgur.com/zXgVIZ3.jpg
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:
https://www.youtube.com/watch?v=0_pB2R9KNzg
https://www.youtube.com/watch?v=Y7RSfVqbjSo

Some basics in heat treating hand tools:
\"How To Heat Treat / Temper Hand Tools & More!\"
https://www.youtube.com/watch?v=I9lgwNp7v0E
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.

 I didn\'t get my point across. You posted what was supposed to be the
smallest screw in the world.

It had a a head the was 0.3mm across. Why would you need a screwdriver
that is 0.1mm wide for that screw.

I think that would be a bad choice, It seems to me a screw driver 0.3mm,
or 0.25mm  wide would be better.

Does Klaus have a screw that is smaller than the worlds smallest screw?
OK being a little factitious there.

Klaus, how wide is the slot on the end of the screw you are working on?

I just took some pictures

Watch disassembled:

www.electronicsdesign.dk/tmp/watch/1.jpg

Screw and 0.2mm sensor blade

www.electronicsdesign.dk/tmp/watch/2.jpg


It\'s a little to wide to fit in the flat slot, so I figured I needed
0.1mm screwdriver

Picture of sensor blade:

www.electronicsdesign.dk/tmp/watch/3.jpg

It\'s a citizen divers watch

 

[Jeff Liebermann]

On Sat, 28 Nov 2020 23:36:19 +0100, Klaus Kragelund
<klauskvik@hotmail.com> wrote:

www.electronicsdesign.dk/tmp/watch/1.jpg

Screw and 0.2mm sensor blade
www.electronicsdesign.dk/tmp/watch/2.jpg

It\'s a little to wide to fit in the flat slot, so I figured I needed
0.1mm screwdriver

Picture of sensor blade:
www.electronicsdesign.dk/tmp/watch/3.jpg
It\'s a citizen divers watch

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:
<https://twobrokewatchsnobs.com/citizen-eco-drive-promaster-diver-review/>
Using the photo #1
<www.electronicsdesign.dk/tmp/watch/1.jpg>
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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150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[speff]

On Saturday, 28 November 2020 at 19:23:14 UTC-5, jeff.li...@gmail.com wrote:

On Sat, 28 Nov 2020 23:36:19 +0100, Klaus Kragelund
klau...@hotmail.com> wrote:

www.electronicsdesign.dk/tmp/watch/1.jpg

Screw and 0.2mm sensor blade
www.electronicsdesign.dk/tmp/watch/2.jpg

It\'s a little to wide to fit in the flat slot, so I figured I needed
0.1mm screwdriver

Picture of sensor blade:
www.electronicsdesign.dk/tmp/watch/3.jpg
It\'s a citizen divers watch
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:
https://twobrokewatchsnobs.com/citizen-eco-drive-promaster-diver-review/
Using the photo #1
www.electronicsdesign.dk/tmp/watch/1.jpg
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.
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Here is a Swiss datasheet that shows the tip dimensions for various sizes:

https://www.bergeon.swiss/synchronisations/pdf/8018%20A%20B%20C.pdf

Screen capture in PNG: https://i.imgur.com/B9o9zOG.png

At $300 for a set of 10 with a rotating base, not inexpensive, but the tips are replaceable.
Tempting if you like nice tools, the tips are going to be properly formed and heat
treated to be hard yet not too brittle.

Best regards,
Spehro Pefhany