I've got a Seamaster Aqua Terra with a 2500C movement. It runs too slow. I'd like adjust the balance like I've done on tons of conventional movements. These balances have two screws to adjust the rate but unfortunately they're not slotted, they have square heads.
Has anybody had a luck turning these without the special tool that's available?

 

If you don’t have the special tool, consider this!

 

Let someone with the appropriate training do this. If you don't know what you are doing, just moving the balance in the wrong direction can damage the escapement. These are very different from a traditional lever escapement.

 

I ordered the special tool a couple days ago. I'll keep you after it's received and I do my adjustment.

 

Do you understand the things that should not be done while doing this kind of adjustment? Strongly recommend you don't do this yourself!

 

That isn't a trivial DIY job, it should be left to a professional. At best you will put the balance wheel out of err balance. At worst cause serious damage

If you do bugger up your watch it may be best not to bother Archer with it and instead send it direct to Omega. It won't be cheap to fix.

 

I'm curious as to how difficult this would be compared to using a micro-stella tool to adjust the timing of a Rolex.

 

"Difficult" is probably the wrong word. None of this is difficult if you know what you are doing.

Adjusting any balance that has timing screws or weights requires that you move opposite pairs of screws exactly the same amount, or you will introduce a poise error. So even if the OP reports back that he has successfully adjusted the rate faster, the chances are that positional variation will suffer because it takes very little difference in the adjustment from one screw to the other to introduce a significant poise error.

The issue that is specific to the co-axial escapements is how the locking and unlocking of the escapement works. With a Swiss lever escapement moving the balance wheel in one direction or the other is not really a big concern, but if you take that same approach here you can very easily damage the escapement by moving it in the wrong direction at the wrong time. You need to fully understand the sequence that the escapement goes through to understand when you can move the balance in one direction or the other.

It seems the OP is determined to do this on his own, and that's fine. He's been duly warned so now it's in his hands. I predict the report back will be complete success, regardless of the outcome.

Cheers, Al

 

Thanks for the info. I'm still going to have a go. I'll keep you updated.

 

Good luck and keep in mind if you do damage it, Omega may not be able to save you as it can be seen as third party work, in this case it obviously is. Again good luck and just making sure you're aware of the consequences whether good or bad.

 

I think this would be a good time for everyone to check their pantry for popcorn, this should be interesting.

 

Putting this here, so I can see what happens....