Regulating Raketa 2609 HA - what’s causing this?

[Zendoc]

Hello all and Happy New Year.

I’m new to this magic of wheels and would appreciate some advice so I can learn.

I’ve just finished servicing a Raketa Kopernic with 2609 HA movement and have found a big difference in rate, dependent on position. I don’t recall this being the case prior to the service.  I demagnetised the movement prior to regulation using my Elma Antimag.

The timegrapher shows nice steady traces and I can regulate the dial up position to +4s/d but here’s what else I find:

Dial Up: +4s/d,  amp 330,  0.0mS 

Dial down: -45s/d, amp 286, 0.0mS

Crown down: -42s/d, amp 289, 0.0mS

I can adjust to the following rates:

DU: +15s/d

DD: -20s/d

Crown Down: -11s/d

Which will average things out over those 3 positions, but my question is - what are the possible  causes of the big difference between the Dial up and Dial down rates?  What have I done or not done during the service which has caused this difference?

Any advice gratefully received.

Cheers,

John in Tasmania.

[Nucejoe]

In general its worn/dirty balance pivot or jewels of cock/ mainplate or impulse also excessive balance pivot end shake. I check the end shake before taking anything apart.

I don't think you are dealing with hairspring intermitent sticking or any part rubbing.

Regs

 

[clockboy]

Agree with Nucejoe end shake could be the culprit particularly with a big difference in performance between DU and DD. If no end shake then re clean the upper and lower cap jewels and re lubricate. 

[JohnR725]

Then it's always nice to show us a picture just because we like to see pictures.

11 hours ago, Zendoc said:

I don’t recall this being the case prior to the service.  

This is where I'd like to record the before servicing and after servicing numbers. It's nice to see a comparison and see if you've increase the amplitude improved the watch etc.

11 hours ago, Zendoc said:

Dial Up: +4s/d,  amp 330,  0.0mS 

Dial down: -45s/d, amp 286, 0.0mS

Crown down: -42s/d, amp 289, 0.0mS

Did you notice an interesting problem here? Who cares about the rate sort of what about the amplitude? 330° dial-up Then you lose 44° dial down and actually have better amplitude in crown down? Typically dial up and dial down should be very very close to identical in amplitude.

Then personally I always like to look at the watch in six positions four separate crown positions and dial up and down.

Here's something fun try an experiment in dial-up let some of the power off the mainspring bring the amplitude down to about 280° and then tell us what sort of time keeping you have? I suspect your regulator pins are too far apart which is why you're having an amplitude timekeeping issue. Then you have to take care your pivots because dial-up and dial down can not be that different it's very bad if a crown position is better then a dial position not impossible but it's just really really bad to do that.

 

[Zendoc]

Thanks everyone for your interest and advice. 

There were two issues, I think.

These movements often have 0, 1 or 2 shims under the balance cock. This movement had 2.  I removed one of them, the end shake reduced and things improved significantly.  I also had a careful re-look at the balance spring and it had a few unusual twists and the end curve was eccentric.  I removed the spring, smoothed all that out, refitted the balance and re-cleaned and lubricated the balance jewels.  

The end result is that the movement is now running nicely - the amplitudes are now as expected.  Thanks JohnR725 for your explanations which make perfect sense. And yes, I’ll get into the habit of documenting the watch performance on the timegrapher before servicing - allows meaningful comparison.  Thanks for the prompt.  As I said, I’m new to all this. Lots to learn.

Thanks again!

Until next time,

John