Hi Folks

When servicing a pw or any other watch for that matter, do folks demagnitize the hairspring or demagnitize the whole watch or not at all? Is this only done if after cleaning no other reason can be found for eratic time keeping? If anyone out there does demagnitize as a normal part of coa, do you use a homemade demagnitizer or a shop bought one? Some suggestions of where to purchase or how to make would be appreciated.

Gordon

Hi Gordon

I generally find I can demagnetizing the whole watch will work adequately, I tend to do this after the watch has been reassembled and just before I start timing out, (don’t forget to do your tools also on occasion) I have a L&R demagnetizer that give a very strong single pulse, on the larger watches you have to hold on otherwise it would pull it out of your fingers!, I do this several times while moving and rotating the watch. There are many good one to be found on Ebay, the coil type works very well also just make sure you have the watch well away before releasing the button, the collapsing field will re-magnetize it if you are to close. You can just demagnetize the hairspring and/or balance complete if you wish, but make sure you wrap it in some watchmakers tissue first to steady the hairspring, if you forget you will get some good practice untangling hairsprings .
As for erratic timekeeping there are many many causes for that one, one common one is that the hairspring is not clean, sometimes you will see the hairspring shake as the leave stick and release, you need to remove the hairspring and re clean, either in a strong soap/water in ultra-sonic rinse and dry and /or one dip, while have the hairspring off, check the balance for poise you will almost certainly find errors there also, examine the staff and check jewels, put balance minus hairspring in to the watch and see if it will half cycle, check end shake, roller to pallet clearances & escarpment operation, is the balance wheel running perfectly true etc, the list is too long to write here. Of course I am assuming you have the hairspring perfect flat and running true and the rest of the watch has no problems and no one has put a erroneous part in to sell it as a nearly running watch, “Just needs a service” .

Hi Chris

Thanks for your advice. The demagnetizers on ebay seem to be made for USA voltage of 110v not our 240/250v. What strength is the pulse on your L & R? How do they rate the strength of the field? This will give me an idea of a size to look for.

Gordon

There are no particular strength just this L&R machine works with a single pulse most common are the coil type, if you do a search on ebay or your local watch supply you should find a machine on 240V 60Hz supply, if you get really stuck you could always get a 240v/110v transformer this would open you up to a lot of cheap tools.

Hi Chris

I intend looking locally for one or making my own from a coil and power source. Are the single pulse better than the coil variety or vice versa.

Gordon

Hi Gordon,

I have used both types and they both seem work very well, I would say just buy the first one that looks in good conditon at the right price! you can always sell it agian should you find a better one later.