Stuck Hairspring Causes?

[TeeJay]

I had a bit of an unusual experience last night, when I swapped back from my 1655 to my Sub. I noticed that the Sub gained about 10 seconds in a minute, and looking at the sweep, it was noticeably faster. For a moment, I wondered if I would need to re-regulate it, then I remembered the talk about the stickng hairsprings and the 'slap fix'. I performed said slap, but left the watch on the shelf over night, just to observe it (and it is now running fine, as before) and I was thinking about what could cause a hairspring to spontaneously stick? While wearing the 1655, the sub was just left on a shelf, no electicals or speakers nearby, so I'm thinking it wasn't magnetism, maybe just the oil sticking, and I wondered how common it was for a 'sitting watch' to spontaneously do this ?

[Rolexman]

There should be NO oil on the hairspring. If there is it indeed could cause sticking. Maybe the balance jewel got over-oiled and the oil has infected the hairsping. The hairsping could also be magnitized. Either way this behaviour is not normal for a clean hairspring and this way you can never rely on your rep telling the right time. I would suggest a dip in 2552 (one-dip) and demagnetization to solve the problem.

[TeeJay]

There should be NO oil on the hairspring. If there is it indeed could cause sticking. Maybe the balance jewel got over-oiled and the oil has infected the hairsping. The hairsping could also be magnitized. Either way this behaviour is not normal for a clean hairspring and this way you can never rely on your rep telling the right time. I would suggest a dip in 2552 (one-dip) and demagnetization to solve the problem.

Thanks for the tips The movement has run fine for at least 18 months without issue, it was the spontaneity of the behavior which struck me as unusual, especially as the 'manual adjustment' ( ) solved the problem. My wife has access to a demagnetizer at work, I'll get her to give the watch a once over with it

[Bike Mike]

Also check the concentricity (Spring coils remain parallel or round to one another) of the spring. The could have caused them to touch. Some time you may have to tweak it to get it back to round.

[TeeJay]

Also check the concentricity (Spring coils remain parallel or round to one another) of the spring. The could have caused them to touch. Some time you may have to tweak it to get it back to round.

Thanks for the suggestion, I'll certainly bear it in mind should the problem recur. I've been keeping an eye on the watch all day, and it's been absolutely fine. I guess it just makes it all the more confusing as the why it happened so suddenly. Maybe the watch was getting jealous that the 1655 was getting wear, so did something to get my attention