Poljot 3133 Chronograph (copy of Valjoux 7734) setting the hammer

[mikepilk]

After many years of servicing my own watches I've finally got round to a chronograph - Poljot 3133, a copy of the Valjoux 7734 (made on machines bought from the Swiss?)

I've got it working OK,  but I'm not sure of the correct procedure for setting the hammer correctly. It's not as smooth as it could be.

I figured out how to adjust the depth of the driving wheel to coupling wheel, and coupling wheel to seconds recording wheel. But it's not clear how the hammer should be set to work smoothly.

First picture is the chrono running. The second the chrono stopped, and the third picture is when Reset is pressed. I know the screw circled in yellow is the one to tweak, but I'm not sure what I'm aiming for !

 

 

[nickelsilver]

It looks fine to me. In a chronograph every single point of sliding friction must be greased, maybe you missed a few points?

[mikepilk]

4 minutes ago, nickelsilver said:

It looks fine to me. In a chronograph every single point of sliding friction must be greased, maybe you missed a few points?

I greased all the sliding points with Molykote DX. I had another tweak and it feels OK.

You can get the hammer in a position where it won't release. I wondered if there was a set position to try to adjust it to.

It's hard to tell only pushing by hand. I'll see once it's cased and using the pushers.

[nickelsilver]

The hammer has 3 positions determined by the cam its attached to and the jumper that positions it. On some of these cam chronos you can get it to leave the zero position and rest in the stop position when moving the operating lever slowly, but in the watch it just (almost always) doesn't happen when using the pushers. I wonder if that has something to do with what you're seeing?

 

Otherwise, chronos can be finicky; some, like the Omega 321 or Valjoux 72 just work fantastically even though the finish on the functional areas of components is often surprisingly rough. Others really need some finesse, a bit of finishing here, some adjustment of spring tensions there, etc. I haven't worked on the Poljot version of this caliber, but have worked on a number of 7733s, and I'm always happy to see them as they just tend to work and run great. Could be there was some finesse lost in the transition to the East.

[praezis]

The yellow screw/eccentric does not adjust the hammer. Its task is to move the coupling wheel away from the chr runner on stop and reset.

Frank

[mikepilk]

56 minutes ago, praezis said:

The yellow screw/eccentric does not adjust the hammer. Its task is to move the coupling wheel away from the chr runner on stop and reset.

Frank

Should the coupling wheel be running when it's not driving the chrono seconds ?

[nickelsilver]

16 minutes ago, mikepilk said:

Should the coupling wheel be running when it's not driving the chrono seconds ?

Yes, it runs all the time.

[mikepilk]

11 minutes ago, nickelsilver said:

Yes, it runs all the time.

Thanks, got it all working nicely now 

(and a nice steady trace with 305° amplitude DU/DD - The Russian movement is working well, despite having spacers under the balance cock)

[mikepilk]

Once cased up, it works smoothly.

What it has shown me is that you need a proper movement holder when working on a chronograph - it's hard to press star/stop and reset without one, and you don't know how the buttons are going to feel once cased.