How to freeze the chrono hand on a 21J Daytona or Speedy (and others)

[NCRich 13,745]

I had been looking around for a tutorial and found this one on the Knitting Circle.  I am assuming this is the best way to freeze the chrono hand on the 23j watches with Chronos.  Those movements, from my research, are DG3836P.  Available on CousinsUK here:

So if you screw it up, you can get a new movement pretty cheap.

Here is the post from the knitting circle:

Freezing a Center Seconds, 3 & 9 Subdials, for what could be a reliable Center Seconds Daytona. (But non-working chrono, so appearance only)

 

What I found, and it can be done....

 

CAUTION - Working on this movement requires a similar skill set to working on a 7750. The Auto-Winding assembly was never really meant to be disassembled on this otherwise 'disposable' movement.

 

Pics to explain it all:

Now put the winding bridge back on.

I'm going to try this soon, @GenTLe is this how you would do it?  I've had crap luck putting winding bridges back on 23j watches.  So I may well destroy mine in the process but you gets lots of tries to get it right.

 

[McGilli 1]

It says file off 3 teeth - but only 2 teeth were filed off  Good luck! 

[Nikosaldente 630]

Thanks for sharing!

I hope it'll work out for you!

 

[GenTLe 1,496]

Never personally did it, but yes I'd do something like that, plus a bit of glue so that the pinion doesn't rotate in case of a rapid wrist movement.

A trick to help you to put back the main bridge is to rotate 180° the triangular bit of the click, so that it doesn't push against the reversing gear preventing the bridge to accept the pinions of the gears below. It is the kind of triangular bit kept in place by the second screw from the bottom in the 4th pic.

You can then rotate it back in normal position after the bridge has been secured

[aitcharGMT 0]

On 2017-12-26 at 06:09, GenTLe said:

Never personally did it, but yes I'd do something like that, plus a bit of glue so that the pinion doesn't rotate in case of a rapid wrist movement.

A trick to help you to put back the main bridge is to rotate 180° the triangular bit of the click, so that it doesn't push against the reversing gear preventing the bridge to accept the pinions of the gears below. It is the kind of triangular bit kept in place by the second screw from the bottom in the 4th pic.

You can then rotate it back in normal position after the bridge has been secured

Yes! Thanks for this to both. I just did this to a cheap DH Monaco!

[gmchris 68]

Wow. That's alot of effort (and skill) for a 21j cheapie.  I think for a Speedie I'd get a quartz version for better subdial spacing - but I'd like to freeze the running seconds @6 subdial. 

Still impressive work tho 

[splke 4,376]

thanks @NCRich but that looks like open heart surgery on a flea

way beyond my strap changing abilities

[BIG GRUNDY 6]

Once again, your dedication to this craft amazes me...  or is it the free time on your hands that I'm envious of

[semperfi55 4,707]

Oooh this guide is a game-changer, might be applicable to the Royal Oak Perpetual Calendar!  Cheers @NCRich

[splke 4,376]

anyone on here successfully carry this out ?  

[BadPickle 2,738]

4 hours ago, splke said:

anyone on here successfully carry this out ?  

 not with your reputation sweetie

[splke 4,376]

Ssshhhh mouth! I was hoping I'd get a vol to do it for me 

[BadPickle 2,738]

11 hours ago, splke said:

Ssshhhh mouth! I was hoping I'd get a vol to do it for me