Hairspring Collet Closure Technique

[fourtimes4]

 I have used a concave stake to carefully close loose fitting collets onto balance staffs. I now have a 1949 Ball Hamilton that has a collet that is stepped. I thought at first maybe it had been altered by someone but I bought another one 1951 and it is exactly the same. The collet is higher on one half than the other half. Guessing I would say by 30 mm which is significantly lower. I am hesitant to attempt to close with a concave stake. Anyone more familiar with this than I am? By the way the collet gap is on the high side of the collet. Any help would greatly appreciated, thanks.

[JohnR725]

The reason why the collet is manufactured this way it's considered a poised collet. It's very common with a lot of Hamilton watches that have this for instance here's the Hamilton deck watch balance wheel

Then the common way to close hairspring balance is with a tool like this normally be really expensive but it looks like the Chinese have cloned the Swiss tool as I swiped this picture off of eBay.

Here's what the original one looks like

From the image above you can see how the tool works and it does work quite nicely for the most part except it can have challenge with over coil type hairsprings. The reason there is a problem sometimes is standard hairsprings like in the image above are pinned in the center versus over coils which are pinned lower down to give greater heights for the hairspring. So sometimes you have to be really careful in your squeezing not to accidentally catch the hairspring and knock it out of alignment.

 

[fourtimes4]

Good information, thank you!

[CYCLOPS]

try closing the collet from the underside