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How-to: the Mysterious Vostok hands mod.

Dave M
October 17, 2010 07:48PM
Or to be a bit more precise, how to do a hands mod when the proper hands are not readily available.

Introduction:
The Vostok 2416b, 2414, and many other Vostok calibers require hands of the sizes:
Hour: 1.38-1.40 mm
Minute: 0.88-0.90mm
Second: 0.16mm or so.

Let's concentrate on the hour and minute hands today. A close match is the 1.50/0.90mm combination, used on many ETA and Seiko mechanical movements. I have selected a hand set from Otto Frei, at a cost of $4.00.

Today, I will demonstrate how to manipulate hand size, in the downward direction.

Tools that I will use:
Starting at the top left, and working right: Dust cover and movement holder, nitrile glove (non-powdered if you have one), dustblower, digital caliper, magnification, tweezer, pin vises, #50 Round smoothing broach, #60 Round smoothing broach, flat-across homemade hand setter, store-bought hand setter, dial protector, #6 Presto hand puller, stick pointed on one end and a glob of Rodico on the other, caseback tool, springar tool.



Other equipment used: Watchmakers lathe















I start by de-casing the movement. This has been covered elsewhere by folks who take much better pictures than me, so I will spare you the details. We end up with the movement, still in it's spacer, in the movement holder. Dial protection is used, and we remove the hands with the hand puller.



We gather data. Use the dial protector! This Vostok has an hour pipe of Diameter 1.40mm, and a cannon pinion of diameter 0.9mm. So, we must modify the hour hand.
















Let's stop here and make an observation. Ask any machinist, we cannot make a hole smaller by removing metal. But most Hour and minute hands have a "stovepipe" extruded out the back. We will get this stovepipe to go smaller.



Let's get some more data. The outside of our "stovepipe" is 1.71mm.



I have a 1.6mm collet, and a 1.8mm collet. I choose the 1.8, and mount it in the headstock of the lathe. I use the tailstock to center and guide the "stovepipe" into the collet. Then we tighten the collet, and back off the tailstock. We tighten some more, squeezing the stovepipe until the hole is just a bit too small.


You don't have a watchmakers lathe, you say? Try the same technique using your pin vise. If the jaws are fairly sharp, and you exercise care, you can do it.



Keaton, our own Watchmaker-on-staff, once told me that one can also use the hairspring collet tightener tool for this same purpose.



Also, if a Seitz jeweling press is available, there is a special die designed for this same operation:


In my case, the idea is to go from 1.5mm to 1.4mm. It is a small amount of distance, but it makes a big difference on whether the hand will spin around loosely on the pipe, or not be able to be installed at all.













There is a lot going on in this picture:

The smoothing broach is round, tapered, has a slightly rough surface, and has had some kind of heat treatment.

I have used the calipers to find the place where the diameter of the broach is 1.38mm. And, I have tightened the pin vise onto the broach at that precise location.

All I have to do is work the hand down, until the "stovepipe" reaches the jaws of the pin vise. I use a twisting motion as I do so.

The smoothing broach will burnish smooth, make round, and properly size the hand, in one operation. Be careful, work slowly, and be aware that watch hands will bend or break if too much torque is used.

If the minute hand needs modification, repeat the process.
















Let's try the hands. They now fit properly.

My preference is to hold the hands with Rodico as I use the hand setter. Also, I find myself frequently using one glove on my left hand. I can hold a movement with my left hand, without leaving fingerprints. Meanwhile, my right hand usually touches only the tools. It's a combo that works for me.


All three hands are on:






And, recase.


How about a gratuitous lume shot?


In conclusion, this operation can be risky. Damage to the hands can occur. Today, I was working with hands that cost $4.00. I am willing to risk ruining a $4.00 hand set, but I don't know if I would be willing to risk damage to a $20 or $30 set.



Edited 1 time(s). Last edit at 10/18/2010 12:22AM by Dave Murphy.
SubjectAuthorViewsPosted

How-to: the Mysterious Vostok hands mod. Jpeg Attachments

Dave M10374October 17, 2010 07:48PM

Re: How-to: the Mysterious Vostok hands mod.

MO Tang59March 22, 2014 01:56PM

You're Welcome to PMWF! (n/t)

Dave M27March 22, 2014 03:21PM

Re: How-to: the Mysterious Vostok hands mod. URL

fizzbin1701101January 23, 2014 04:11AM

Welcome to PMWF! You say that you are confident that it will fit >>

Dave M105January 23, 2014 04:15PM

And by the way, the odds of a Royal Fizzbin are astronomical. laughing laughing (n/t)

Dave M67January 23, 2014 04:23PM

Wow great work

noah549October 25, 2010 04:09PM

Thanks, Noah. Yes, I'm a Rodico addict. laughing (n/t)

Anonymous User580October 25, 2010 06:41PM

Re: Thanks, Noah. Yes, I'm a Rodico addict. laughing

noah422November 01, 2010 07:22PM

Wow! What an amazingly interesting and informative post!Eek!Clapping! smile Thanks Dave! (n/t)

Nuvolari396October 25, 2010 04:59AM

Thanks, Michael. smile (n/t)

Anonymous User368October 25, 2010 11:38AM

Excellent! Pin this one! Cheers! (n/t)

VoodooDance439October 21, 2010 03:45PM

Thank you! Chester. laughing (n/t)

Anonymous User440October 25, 2010 11:37AM

Wow, very cool Dave! (n/t)

baumer375October 19, 2010 03:40PM

Thank you! Eric. smile (n/t)

Anonymous User354October 19, 2010 06:39PM

Excellent post Dave Thumbs up! (n/t)

Anonymous User599October 18, 2010 05:12PM

Thank you, Adam. smile (n/t)

Anonymous User428October 18, 2010 05:30PM

Great tutorial, Dave! Clapping! (n/t)

MCV390October 18, 2010 04:21PM

Thank you! Marc! smile (n/t)

Anonymous User490October 18, 2010 05:30PM

A great informational post, Dave. Thanks.SmileThumbs up! (n/t)

Mark C.497October 18, 2010 01:56PM

Thanks, Mark. smile (n/t)

Anonymous User435October 18, 2010 04:05PM

Great post Dave, I have marked it for the archive Thumbs Up (n/t)

Reto355October 18, 2010 06:47AM

Thank you! Reto, I will move it to the MOD forum in a couple days. smile (n/t)

Anonymous User408October 18, 2010 11:42AM

great post, just love the SUS hands. wink (n/t)

sharkfin365October 17, 2010 10:06PM

Thanks, Dave. I agree, they seem better matched to the >>

Anonymous User402October 18, 2010 01:06AM

Nice job. Definitely one for more permanent storage! (n/t)

Smaug365October 17, 2010 09:38PM

Thank you! smile (n/t)

Anonymous User507October 18, 2010 01:19AM

Oh yeah!! Dat's my Pard! Thumbs up! Clapping! Clapping! (n/t)

JohnnyT412October 17, 2010 09:13PM

BTW Dave, does that alter the length of the stove pipe? EG might it not reach the pinion? (n/t)

JohnnyT345October 17, 2010 09:15PM

Thanks, Johnny. As Ricky said, the effect will be >>

Anonymous User347October 18, 2010 01:13AM

WinkRe: ..four thousandths of an inch. A bit more than the breadth of a human hair,

Anonymous User456October 18, 2010 02:09AM

Rolling on the floor laughing my a.. off Rolling on the floor laughing my a.. off Yes, Ricky, I thought about >>

Anonymous User404October 18, 2010 11:40AM

I was about to inquire about a machinist's familiarity with a

JohnnyT422October 18, 2010 03:01AM

It will. But the change will be a few MICRONS, so not to worry. Wink (n/t)

Anonymous User381October 17, 2010 09:36PM

Clapping! Clapping! Clapping! (n/t)

Anonymous User378October 17, 2010 08:43PM

laughing laughing laughing (n/t)

Anonymous User332October 17, 2010 08:48PM

Cool stuff Dave! (n/t)

DJM357October 17, 2010 08:38PM

Thank you! Dan. smile (n/t)

Anonymous User316October 17, 2010 08:47PM

wow....miles ahead of anything I'd attempt Thumbs up!

greg honeycutt380October 17, 2010 08:35PM

I have attempted this operation. But..

Anonymous User404October 17, 2010 08:47PM

Those Elves did a nice job on your crystal, so maybe they can do this, too. >>

Anonymous User392October 17, 2010 08:57PM

Re: But even if you have a 33% success rate, that puts you at a $12 fix with Uncle Otto's hands.

Anonymous User431October 17, 2010 09:25PM

Re: on such a small scale...

Anonymous User408October 17, 2010 08:47PM

reminds me of when I was learning how to make round shapes out of flat metal. Thumbs up! (n/t)

greg honeycutt334October 17, 2010 08:51PM



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