Greetings all,

I've been discussing a vintage watch with a seller, and when I asked him whether the watch keeps time he answered he was happy to get it serviced before shipment. I said I'd prefer to do so myself, here's what he replied:

QUOTE
"I don't see any issues with the watch. I have only had it for a few months and hadn't checked it, so when you asked, I
I did a quick check and found it gaining 5 seconds or so a minute. It can be easily adjusted but I just assumed it hadn't been serviced and thought it might need it so I offered you a service just to be sure."

I pointed out that a gain of 5 seconds per minute means 2 hours per day, tried to talk him out of servicing the watch and instead suggested he observe the watch for 48 hours.
He replied the following:

"Thanks for your suggestions but I really don't think your procedure is necessary within the terms of the time gain I have set out. The watch TRAIN seems to work fine so the probability is that the balance is simply magnetised, giving the inordinate results on the few-minute test. I now further see that someone seems to have noted the gain and tried to adjust it and the F&S regulator is at the END of its travel while the time-measurement still seems to indicate a massive gain. Indicating magnetic influence. This is a ten second remedial procedure but I still think the watch must need servising so while I am at my repairer, that is what I will do
Thank you again for your interest and suggestions"
UNQUOTE

Can someone explain what this means?
Thanks and best regards,
S

 

It would have been helpful if you had given some information about the watch! Some vintage, and many antique watches have steel balance wheels and hairsprings which become magnetized easily. This seriously affects their timekeeping. De-magnetizing them is easily done. What disturbs me is that the seller hadn't had the watch serviced and the rate checked, before offering it for sale! I suggest that you establish clear terms for returning the watch before you accept the deal, and have it checked, yourself. Let us know how w how this turns out.

 

http://wornandwound.com/watches-and-magnetization/

Bottom line - yes, magnetic fields can affect your watch. The usual symptom is to have the watch run very fast and the cure is to run the watch over a degausser. It doesn't even take 10 minutes (mis-read your original - yes, a few seconds is all it takes). Last year I had a watch that seemed to have become magnetised (I still don't know how but high powered magnets are more and more common in every day life). I'd decided a trip in to my watch repairer was in order but in the intervening days, the watch corrected itself and wasn't problematic again ... though it is with him now as it's due some tlc.

 

The most common problem arising from magnetism (on both vintage and modern watches) is that the balance spring is magnetized, causing the coils of the spring to stick together. The length of the balance spring directly influences the frequency of oscillation of the balance. The shorter the spring, the faster the watch will run, and the longer the spring, the slower (all else being equal).

When a balance spring is magnetized and coils stick together, it shortens the effective length of the spring. Shortening the effective length is how regulating pins work also, so this characteristic of the balance spring is both an advantage and disadvantage at times. Demagnetizing the watch will cause the coils of the spring to no longer stick together, and the rate will return to normal immediately.

Magnetism isn't the only reason coils stick together though, as they can also be dirty, oily, etc. and have the same effect. Also, it doesn't have to be coils stuck together that shorten the spring - this can happen in a couple of other ways. One is the spring getting hung up due to a shock - this is a photo of a ladies Rolex movement, and it shows the balance spring as it should be:



A shock can cause one or more coils of the spring to get caught on something, in the case below on another ladies Rolex movement it's the stud:



This watch gained time much like it was magnetized, but this situation happens because of a shock.

Another cause would be if the spring breaks off at the stud for example, and someone just re-pins the spring at the stud - this is a more difficult problem to resolve obviously because the spring is actually shorter, not just effectively shorter.

Note that a fast rate may have many other causes - could be regulating pins that are not set properly, balance spring out of plane or not concentric, missing screws from the balance, wrong balance wheel or balance spring, or it could have nothing at all to do with the balance, and the watch could be rebanking or something else. Impossible to diagnose with certainty with the information provided.

Note that if it is serviced by a competent watchmaker, all these scenarios would be looked at to resolve the problem during a service. It's common practice that all watch movements are demagnetized after cleaning and assembly, and before any adjusting or timing is done.

Cheers, Al