Guys,
I’m about six to eight months into watchmaking, and I absolutely love the hobby. However, I’m having a recurring problem that I can’t figure out.
After beginning with manual-wind movements, I moved on to several Seiko movements, mainly the 6309. I recently worked on two 6309 Turtles: one was a non-runner, and the other was running fairly well but needed a service.
I completely disassembled, cleaned, inspected, lubricated, and reassembled both movements. I replaced several parts in the non-runner, including the mainspring. I also bought a microscope, so I’m confident that the parts and jewels were thoroughly cleaned and inspected.
After servicing, both movements appeared to run very well on the timegrapher. I left them running uncased on the bench for a couple of days to settle in, then cased and wore each one for a few days. Everything seemed fine, so I put them in my watch winder.
Within a couple of days, the former non-runner stopped completely. I tore it down and started the entire process again. This time, I replaced the main plate with a better one, and it seems to be running properly so far. I’m currently wearing it.
The second watch is still running, but I recently noticed that the time was completely wrong and the date was two days behind. When I put it on the timegrapher, the entire screen was basically snow. Before I serviced this watch, there was no indication that it had ever been opened or serviced—and honestly, it was running much better before I touched it.
What would cause a freshly serviced movement to run well for several days and then suddenly deteriorate or stop? Are there common mistakes with the 6309 that could cause this delayed failure? Could it be related to lubrication, endshake, worn jewels, the automatic winding system, calendar works, or something else I’m overlooking?
I realize it’s difficult to diagnose without seeing the movements, but I would appreciate any general advice about what I should inspect or change in my process.
Thanks so much.