A friend of mine asked me to take a look at his father's Hamilton w/w grade 982. I usually only work on American pocket watches but told him I'd take a look. I took the watch down for a cleaning and oiling and also to replace a broken mainspring. I noticed that the hairspring is a lot weaker than pocket watches. My question is, when puting the balance back on the balance cock is this done out of the movement or do you put the balance back in the movement and then attach the hairspring to the balance cock? Is the hairspring strong enough to support the weight of the balance if I install it on the balance cock first, like I do with pocket watches?
Thanks for any help you can give me on this. It really feels funny asking a repair question.
Brian C.

pwpartsetc@pwatch.com

Brian,

Many wristwatches have balance wheels that seem unusually heavy for their hairsprings, and as in a related topic currently being discussed, the reason for that is "moment of inertia."

Since wristwatch movements are much smaller than those in pocket watches, their balance wheels have to be smaller as well. Particularly in rectangular models, that causes serious issues with available space, and the diameters of the balance wheels are reduced even more in order to fit. Of course, in order to bring a watch to time with a balance wheel of a smaller diameter, it's necessary to use a weaker hairspring, and therein arises the problem you've encountered.

In many wristwatches, the balance has a relatively small diameter, but it's unusually heavy in relation to the size of the hairspring. Again, that's due to "moment of inertia," but the result is that it's often a bad idea to try to "support" the weight of such a wheel by the hairspring.

Whenever I have ANY doubt, I remove the hairspring stud from the balance cock BEFORE removing the cock, and I replace the wheel and cock before replacing the hairspring stud upon final assembly. Particularly in Gruen models with a "Conoruma" hairspring, following that advice will save lots of grief.

The balances in Hamilton 980 and 982 models should withstand being supported by their hairsprings under ordinary circumstances (unless one happens to drop the whole assembly), but there really isn't any benefit to risking it when there's a much easier and safer way.

As always, I hope this helps!

==========================

Steve Maddox
Past President, NAWCC Chapter #62
North Little Rock, Arkansas
IHC Charter Member 49

Good Question Brian,

I wonder that same thing myself as I start on repairing wristies.

I have tried replacing the stud in the balance cock while it is attached to the pillar plate and it is tricky.

A virtual impossibility though is turning the "boot shape" regulator pins (that are slotted on the bottom). Is there a trick to this? or is one left to simply push them from the side with a small screw-driver?

Mike Miller

Mike,

The Hamilton upon which Brian is working doesn't have a "boot-shaped" regulator stud, but for watches that do, there's a little "wrench" specifically made for that purpose. The one I use is made from an old section of mainspring with a notch in the end, but "store-bought" models are (or used to be) available as well. Some regulator studs of that type also have a hole drilled crossways through, which is intended to facilitate turning them with a sharp probe.

A few people have been urging me to write an instructional book about watchmaking, but the more I think about it, the more apprehensive I become. There are so many little "tricks" like the one above, I'm afraid I'd end up with a book thicker than the Bible, and no one would ever bother reading it!

For those who like "hefty" books, both in volume and content, a good choice would be "Morals and Dogma," by Albert Pike. It's worthwhile reading, but I've been told it's the most widely published, and least read book ever printed.

====================

SM

Thanks Steve,
I put the balance in first and then the balance cock. It was a little tricky getting the hairspring in the regulator pins but it all went well and the watch is running fine.
For the people just starting to learn repair. I have been repairing pocket watches for about 15 years. This just goes to show you, never be affraid to ask questions first, then go on to repair. You can learn something every day in this trade.
Brian C.

pwpartsetc@pwatch.com