Balance stops

[Bopmd]

I tried looking for this very question, but couldn't find anything similar. 

Hello! I recently started putting a omega 1012 movement together. Everything seemed normal until i was going to screw the balance in. When i tightened the screw, the balance stopped. If i untighten the screw a little the balance starts swinging again. The balance starts swinging when I unclip the incabloc spring on the dial side too. 

What could be the cause of this? And would it be ok to just leave the screw slighly untightened? 

Thanks for replying

[Nucejoe]

Distance between upper and lower end stones is less than the length of balance staff, whereas if should exceed it by .02 mm. this .02 is called the end shake. there are many ways to adjust for decent end shake. Shimming, whereby you put a shim of say aluminum foil underneath the balance cock then go on with tightening the cock screw. you can also move the lower jewel assembly outward, if it is movable.

[Joseph111]

This can sometimes also cause low amplitude. It is not generally deemed a good idea to do so but some manufacturers (mainly in China) make a small notch using a graver either on the balance bridge or base plate in order to do the same as what Nucejoe suggested.

I think Mark showed it in a video at some point and someone had done the same thing to a Pierce 160/22 movement I was repairing.

[rodabod]

Was the balance working ok previously? If yes, then most likely cause in my experience would be the pivot not seating correctly in the jewel hole. Often the jewel hole chaton and cap jewel position will be the cause. Try removing and re-seating the jewels while the balance is installed (but not overly tightly as you suggest!).

[HectorLooi]

I encountered this problem once. Then I learnt from 1 of Mark's videos that it can happen if you mix up the upper and lower incablocs.

I had taken out both incablocs and cleaned them in lighter fluid. I assumed that cap stone, jewel hole and upper/lower position shouldn't matter. Well, it seems that it does.

I had to go through a few combinations/permutations of cap stone, jewel hole and position before it would work properly.

Weird. 

[Nucejoe]

Endstone Mix up dose not alter the distance between the two, it dose however move the balance staff thence all attached to it.

[Bopmd]

Okay so the cap jewel was placed the wrong way and the dome went inwards... Should've checked that earlier... Thanks for all the answers!