A little background information. This 992 was running slow before I started working on it (10 min/day). Since I have successfully worked on two Elgins, I decided to try the 992. It is missing one pallet bridge screw, but the bridge seems secure enough for bench testing until I get a screw.

I did not replace any springs since I don't have them on hand. The mainspring seems in good shape.

The Hairspring has slight surface rust in several areas. (maybe a weak Hairspring?)

The mean timing screws are almost all the way in.

The regulator is advanced all the way.

After cleaning and lubricating the watch, it runs better, but not by much. My watch books are in the mail so I'm looking for a debug sequence that you might suggest. I tried turning in the mean time screws almost all the way a half-turn at a time but with little effect.

Thanks for any debugging suggestions.
David

David,

Did you check magnetism? The biggest headache I ever had was with a magnetized watch. I use a cheepo compass that I hold just above the balance (when running) and movement and see what the needle does. You may be suprized.

OK - stupid beginner question - but - what should the needle NOT do? I've read some on the web about magnetism, but how can you tell between good and bad. I'm assuming that you would not want the needle to move much, if any. You would think that it would move some due to the metal moving.

-David

David, Very little or no movement should be seen. The needle should point north and thats it. If the balance is magnetized you will see the needle move back and forth with the balance. I have also seen mainsprings magnetized and this will draw the needle straight to it when the compas gets near.

No questions ever aksed are stupid ones, by the way.

OK.... I'll try tonight and see what it does.

-dd

So I tried the compass. It only twitches slightly in time with the beat. It does not swing, but just moves slightly. Is that enough to be a concern?

Thanks,
David

Slow running movements could be caused by several things. To try and decipher what's going on you might try the following:

(I take it that you don't have a timing machine that would speed up the process. But all is not lost. The old fashioned way works but takes time)

With an accurate quarts timer syncronized with the 992, fully wind the watch and place it dial up position. Then note how the 992 keeps pace with the quartz watch (a few hourly readings in the beginning and end of the timing period would be good). I usually create a table listing the deviations. Run it through 24 hours and finally note the total deviation for the 24 hour period.

Repeat the process in the dial down position.

Then repeat the process in the pendant up position.


Now look at the results. Does it loose time evenly (averaging say 20 seconds per minute over 24 hours)? or does it loose most of its time in the last few hours of the wind? does it loose more time in one position than another?

I know that it sounds mind-numbingly tedious to do this. But the resulting information will go a long way towards diagnosing the problem.

Some other things to look for... bad pivots on the Balance Staff (pitted or flattened), bad hole jewels, loose roller jewel, loose balance screw, balance badly out of poise.


Keep us in touch with your findings, and we can help decipher what's goin on.

So, I think I *might* have found the problem. The upper balance staff pivot post (is that the right name?) seems to be bent slightly. I'm assuming that this would cause the watch to run slow. I'm pretty sure that it would break if I tried to straighten it out.

So - would this cause the watch to run slow?

I guess I did not inspect the balance staff closely enough.....

-dd

David,

A bent pivot could cause a watch to run slow. It could be causing enough drag in the hole jewel to slow things down. Looks like this one will need to be restaffed. I wouldn't try to straighten the pivot, since this usually results in poor timekeeping, and 992 staffs are readily available.

Also I reread your first post and see that you mentioned that there is some surface rust on the hairspring. I somehow missed this when reading it first. It is possible that the hairspring could be somewhat weaker as a result, which would lead to a slow timekeeper. Although this isn't always the case.

Staffing is a relatively simple task that can be learned, but does require several tools to do it properly. Should you decide to tool up to do watch repair, I would suggest practicing on some scrap balances before moving directly into the 992,

If you decide to send the watch to someone for repair, you will find that there are several qualified and competent watchmakers who have info in the Business Directory.

Keep us posted and let us know how we can help!

Update:

Just to see what would happen, I adjusted the pivot on the top of the balance. Using 10x magnification and a straight edge from my Mitutoyo Caliper as a guide and a pair of tweezers, I managed to get the staff pivot pretty much lined up. So - I put the Balance back in - better - but still slow. Humm... I took the balance out again and while I was checking it out in my eyeglass loupe, I noticed that one of the screws next to one of the mean time screws was cut off (rather poorly I might add). There was a corresponding cut off screw on the other side also (makes sense). These screws did not match and were put there some time ago. On a hunch, I removed the half screw and the corresponding half screw on the other side of the balance. I put the balance back in, wound up the watch and Viola, it's running very close to on time - even a little fast.

Now - Why would someone put a half screw right next to two mean time screws. In my reading, the area right next to the mean time screws seems to be a "neutral zone" with respect to temperature timing. I have not timed the watch in all positions yet or two temp ranges, but it seems to be running even a little fast (as the mean time screws are still almost all the way in)

That's the update.

Thanks,
David