I have been teaching myself pocket watch repair & one of the most difficult parts I have trouble with is the balance & timing.

Currently I am trying to time a Hamilton 4992B, I clean the watch & replaced the mainspring & everything seems to work well.

I had to replace the hairspring but it appears I have the watch in beat but when I time the watch is runs at a perfect rate of 17685 but I can not figure out how to increase the rate to 18000. Would I adjust the timing screws on the balance?

I am open to any advice, no matter how many books I read on this subject, I am failing to grasp something.

Thanks for any help!

Tom

I got the problem fixed, I tried a 2nd 4992B hairspring I had & the rate increased so with some adjustment I have it within 2 seconds a week error.

Tom

Hi Tom, The Hamilton 4992B has most of the same parts as a 992B, and there are at least 3 different hairsprings for that model. Weak, medium, and a strong. I assume these where used for timing problems.

Just thought you might want to know.

Thanks Leon, I didn't know that. Maybe that was the difference in the 2 hairsprings I tried.

Tom

Hi Tom, check out the picture. I picked these Elinvar hairsprings up on ebay last year.

Leon

Want to sell one?

Tom

Hi Tom,

it is good that you fixed the problem by replacing the hs and hopefully you may get another one.
Just to answer theoretically to your initial question, if you have a ''slow'' balance you have several options to make it go faster without changing the hs...

- shorten the hs at the stud' end ,
- screw in the balance screws, then recheck for poising,
- undercut the balance screws , then recheck for poising,
- substitute the balance screws with lighter ones, then recheck for poising,
- remove opposed screws starting from the ones farthest from the balance arms, then recheck for poising,

You can alter the order of the last 3 at your convenience and skill.

just to mention the most common.

Naturally a proper hs is a much better solution as you have noticed but as a matter of researching the above are all related to the problem you have incurred.

rgds

Enzo

Thanks Enzo

Before I decided to put the 2nd hairspring in I did screw the mean time screw all the way in but that only brought me up to about 17750, I had read that next was the undercutting but I thought I would try the 2nd hs 1st & sure enough I had to back the screws back out to their orginal position.

Tom

Tom,

yes, it is a complicated adventure to go that way, it is just good to know that there are ''last resources'' for desperate cases....
Incidentally by reading with interest your post I was amazed how accurate in timing the 4992B can be....not many watch around can be that precise...you have a good lab , i understand, but also that type of mvmt shows an accurate design and crafting...it is a pity that all that is gone.....
rgds

Enzo

Tom, email me at HarrisLJ@msn.com and let me know which one one need.

Hey Tom, all is not gone, there are still manfacturers of high quality manual watches but they cost a bomb. And unfortunately they are not made in america.

Tony

Enzo, if, as I do, I have fast watch and no HS availble for it can I do the opposite of what you suggest with the balance wheel weights to slow it down?

Tony

There are entire books written on the subject of watch timing. Enzo touched on a few of the items that affect timing. If your watch is fast, the first thing I would do is demagnetize it and check again. Also look very closely at the hairspring and make sure there is no oil or residue on it and that it is not touching the bottom of the balance cock or balance arms. (That would usually make it slow, but not necessarily) Check the regulator pins and make sure they are vertical and not pinching the hairspring. There should be a small gap and the hairspring should alternate between pins when running. This adjustment can make dramatic changes to timing. Of course all of the above assumes that the watch has been serviced and the balance jewels have been cleaned and properly oiled as well as the staff pivots at least cleaned and possibly polished. Also that the mainspring is good and the train and its pivots and holes, whether jeweled or not, are all clean and good. Bottom line, whether fast or slow, the last thing you want to do is start working on the balance before all other avenues have been examined.

Thanks Roger, good advice, those big changes I assume can be difficult to revert easily.

Just to test, I placed the clock stem up, normally it is stem right. I this stem up position it held time.

I might take it more slowly before doing anything silly.

Tony

Tony,

You may have a balance out of poise or a hairspring that is not concentric. Look closely at the hairspring and see if the coils look evenly spaced both static and running. If they are not, this should be corrected, but if you don't have hairspring tools and some experience with hairsprings, it may be best to leave it for someone who does. To poise the balance, the hairspring is removed and the balance assembly with roller table attached is placed on a poising tool and weight is added or removed to poise the balance. Calipers can be used, but it is more difficult. Weight is added with timing washers placed under the screws and removed with undercutters. I avoid cutting screws as much as possible since this is a permanent change. You also have to keep the total weight of the balance assembly very close, but that is another issue.