Hairspring alignment

[bigd]

I was just watching the video "how to fit a new balance staff to a Rolex". Great video as usual, but leaves me with an unanswered question; namely, how is the position of the roller fixed relative to the hairspring stud or fixing point such that the balance is in beat?

[jdm]

9 minutes ago, bigd said:

I was just watching the video "how to fit a new balance staff to a Rolex". Great video as usual, but leaves me with an unanswered question; namely, how is the position of the roller fixed relative to the hairspring stud or fixing point such that the balance is in beat?

With a moveable stud arm:

 

If it is not:

 

[bigd]

Thanks for the quick reply. The movement is a Rolex 2315 which is free sprung, so there is no stud arm. Yes, I could move the hairspring, but in the video you will notice that Mark fits the roller and the hairspring with no mention of their alignment. Am I missing something?

[jdm]

39 minutes ago, bigd said:

Thanks for the quick reply. The movement is a Rolex 2315 which is free sprung, so there is no stud arm.

There is no regulator and no regulator arm. 

The hairspring stud is the small body that ends the outer portion of the hairspring.

[oldhippy]

If there is no friction fit stud.  You have to fit the hairspring to the balance so the roller is in the center of the pallets.  Most repairers will mark on the balance the position where the stud should be . This helps when fixing it all back in place. 

[jdrichard]

If there is no friction fit stud.  You have to fit the hairspring to the balance so the roller is in the center of the pallets.  Most repairers will mark on the balance the position where the stud should be . This helps when fixing it all back in place. 

My work today on a vintage PW, in which I made the balance staff.

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