I am looking for suggestions on one of the things I understand the least.

I have a pocket watch that before cleaning it was running about 18200, I completely disassembled it & cleaned & oiled it, put a new mainspring in but in all positions it still runs at 18200.

I have noticed that the cannon pinion is snugger that most, the time can be set but I have noticed when moving the hands backwards it will actually stop the movement. Could a too tight cannon pinion cause the watch to run fast. That doesn't make since to me but thought I would ask.

If a watch was in time at some point in in it's history and wasn't fooled with would just age cause it to speed up.

The watch is now running at 18200 & only varies to 18199 in all positions but before I start messing with things I am just trying to understand what would cause it to run fast.

Also I check it for being magnetic but it seems fine.

Thanks for any suggestions.

Tom

Hi Tom,

The cannon pinion, would not cause it to run fast, however you have demonstrated why it is not good to wind the hands in reverse this overlay tight cannon pinion is driving the train backwards even with a correct cannon pinion tension winding in reverse will apply a certain amount of pressure and will effect the running of the watch to some degree whilst doing so in a forward direction also. I would try first removing the cannon pinion and applying a small amount of whatever grease you use to the inside re fit and retest for correct tension, if still tight examine you may notice someone has put a huge dent in the side, you will have to carefully ream it out adjust and refit.
The timing is somewhat odd, that its running well in all positions albeit at 18200, that says it is in good poise, and many adjustments spot on, have you tried to run it for a few hours and check it is actually not keeping time? (we are assuming 18000 is correct what are you working on anythign odd?) If it was off a couple of hundred and different in positions I would just say it needed timing out after previous poor adjustments or changes but to be precisely 200 in all positions before and after cleaning,
Have you checked you timing machine against another watch, are all the settings correct, what timing machine are you using? If everything checks out simply correct with timing washers and should have a spot on watch in positions.

Hi Chris

Thanks for the advise. It is a 21 jewel Bunn Special, the timing machine appears correct with other watches. The Bunn is running fast, it has gained 10 minutes in approximately 12 hours.

My timing machine is a Microset.

By the way, I do try to always set the time by moving the hands forward, in this instance I was trying determine what the problem might be.

It seems to be running very well as far as staying ppretty much spot on at 18200 in any position.

Tom

Tom,

i would just scratch my head as to how it got to 18200 and adjust to 18000 could a pair ssmall timing screws been removed? any empty holes with shadows?

Chris

I think that might be it, it would appear the two mean time balance screws are missing from the ends of the balance arm & two other screws have been cut down to where they are almost just posts.

Looking at my other Bunn Specials it does appear someone monkeyed with the screws to speed it up.

I will see what I can do & how it changes the timing.

Tom

Sometimes they will turn the head off one ( as they are tight)and not haivng a spare either try and glue it back on or take the other out to look correctthen sell as is, with these screw missing check the balance staff they may have also bent the pivots while turning the head off the meantime screws no doubt while in the watch
PS did lubeing the cannon pinion free it up?

I haven't done anything yet Chris, was just trying to get some advice before I made things worse.

I don't think whoever did this broke the screws off, the two that are short look like they were cut & polished. It looks like someone was trying to make the watch run fast or else to over come some other problem with the timing.

Thank you for you help, this evening I will see what happens if I 1st just replace the two mean time screws & then go from there.

Tom