Reply To: Main Spring

[arutha]

Like I said earlier I have had the same thing, springs wound fine until I stripped and cleaned. The most common cause Is the inner loop is bent slightly out of shape. Some of these mainsprings are very soft at the ends and it dont take much to bend it out of shape, even just a slight twist to the loop end can cause problems. If you are saying that this is a tight fit around the arbor and the spring jumps of when almost fully wound it can only be one of two things, the eye on the inner loop has a tear or is distorted or the spur has worn. If you are 100% positive the inner loop is ok then it has to be the spur on the arbour. One other thing that might be worth checking is where the arbour goes through the barrel and cap, are these holes worn excessively allowing the arbor to move so much it can disengage with the spring?