Quote Originally Posted by swanbourne View Post
There's a problem with the ST19, either the mainspring it too strong or the barrel click spring is too weak. There's no way of telling when, if ever, it will fail, it could be after months of use and suddenly the mainspring lets go and you can't develop a power reserve. When it was clear that this was a problem, we got new click springs made and replaced them during assembly of the watches and whilst this reduced the incidence of failure, it didn't eliminate it.

There weren't a huge number which failed but when you have a dozen or so failing with the same problem, it's clear that something is not right. I'm not prepared to continue using this movement as long as the problem exists.

Eddie
Thank you Eddie, very interesting & much appreciated, comprehensively cleared that one up !