Roller adjustment

[margolisd]

Hi folks. For watches where you can't set the watch in beat by adjusting the position of the hairspring stud, my understanding has been that you must reposition the collet. I always find this incredibly tricky and dangerous. Once or twice my screwdriver has lost traction on the collet and I've damaged the hairspring resulting in much swearing. I just stumbled across this tool. Doesn't it make much more sense to use one of these to adjust the roller? Am I missing something?

https://www.cousinsuk.com/product/roller-adjusting-tweezers

[Jon]

Turning the collar on the staff will move the jewel and the hairspring stud further or closer to each other, but turning the roller, will move the jewel but the relative distance between the jewel and the stud will remain the same. In effect, the only thing that is turning is the balance staff. That's what I can see is different between the two methods. So really, the only way to bring the watch into beat is by turning the collar on the staff. I could be wrong, I'm going out on a limb...

Edited September 14, 2018 by Jon

[margolisd]

...Oh. So this tool would effectively only rotate the wheel on the staff?

[Tmuir]

When you remove the roller for what ever reason you want to try and position it back in the same place, that is assuming someone else hasn't already been at the watch and replaced it incorrectly previously.

The reason being if you place it differently it could impact the poising of the balance staff.

On a 2 arm balance staff the impulse jewel is generally positioned 90 degrees away from the balance arm.

I would of thought you would use that tool if when placing the roller jewel on you needed to adjust it to get it back to the correct spot, not for getting the watch in beat as you should be able to do that with just adjusting the hairspring unless you placed the roller jewel back on in the wrong spot.

If you look at balance from a vintage watch you can usually spot tiny marks on the balance rim that a watchmaker did in the past to show where the impulse pin should go and the hairspring stud to put the watch in beat (and hopefully keep it in poise).

 

[clockboy]

I have that tool and the first time I used it it slumped dipped and I broke the the tip-off the balance staff. Hence I have never used it since. When moving the collet I make a mark on the balance rim opposite the split in the collet with a very fine maker. I then insert the smallest screwdriver I have (0.50mm) into the spit and turn the balance a minute amount. When putting the watch back on the timing machine you should then see if the direction you have moved it is the direction required. Note the recommended tolerance of beat error should be +/- 0.4ms but achieving this can be challenging. If I get a watch into the 0. area  I settle for this. 

[margolisd]

Ah, thanks all. That's really interesting stuff. So the position of the roller relative to the wheel is actually important for poise.

Yes, I often see the lineup marks left by other repairers and I've made a few myself to make it easier.

I really like the idea of using a fine marker to record the position of the split. I will try that out. Thanks

[chadders1966]

Hi

This is the Bergeon 30017 version of the tool used for adjusting the collet, comes in different sizes. Obviously pricey for what is essentially a hollow tube to fit over the pivot with a slight nib for fitting in the split on the collet. I picked some up second hand, perhaps simple to make your own? I find it a lot easier and safer than using a screwdriver.

Stephen

https://www.hswalsh.com/product/bergeon-30017-ttp-tool-hairspring-collets-hc30017-ttp

[nickelsilver]

The roller can be moved to make slight adjustments to the beat. There were fairly elaborate tools made for this (will post a pic when I'm back in the shop). If the staff moves in the balance when moving the roller then the staff was not rivetted properly.

Large adjustments must be made at the hs collet to keep the poise and balance position correct. Fine adjustment at the collet is usually easier as well unless the above special tool is on hand. The tweezers are just too awkward. A microscope helps, the angular movement can be really tiny.

The tweezers from the OP are handy for adjusting a roller position after a restaffing or for getting a roller off when other methods don't work.

The tool for turning the collet is good and works well and safely as long as the cock can be manipulated far enough out of the way, not always the case.