What is this tool?

[LittleWatchShop]

I got these in a bulk purchase of tools on ebay.  I think these are hairspring tools.  On one end is a hollow tube with a tiny notch.  I think it is for turning HS collets while mounted on the balance wheel.  The other end is for tweaking the spring itself?

[watchweasol]

Hi  LWS   I would aree with you on that, do the hollow ends have a little projection to fit into the collet gap for turning the spring.

[nickelsilver]

Yes, for turning collets (the end with the little "pip") and otherwise manipulating the spring.

[LittleWatchShop]

here is magnified both ends.

How about the other end...how is it used.  Maybe also a collet adjuster when the balance is attached to the cock?

[nickelsilver]

I use the regular end whether the balance is attached to the cock or not- and also small screwdrivers, or broken oilers that have been reshaped at the end. Depends on the watch. The other end of your does look like it would also work for moving the collet. Whatever you use is OK as long as you don't mangle the spring or kill a pivot!

[LittleWatchShop]

6 minutes ago, nickelsilver said:

kill a pivot

BTW, this weekend I tried to straighten a pivot using your heated #8 tweezer technique.  I improved it, but decided that since a new staff is available, the watch would be happier with it.  Ordered several from Cousins!

[LittleWatchShop]

Well, I put this tool into use this morning.  Working on an Elgin 12s pocket watch.  I needed to adjust the beat.  A little scary...but it worked!  Not sure if it is the correct method, but I put the cock on a balance tack and extended the balance wheel downward so that I could slip the tool between the coil and make the adjustment.  Would have been trivial with the spring removed of course.