1960s Seamaster 600, quite the conundrum.

Hello all,

I am new to the forum so please do forgive me if this is a double, but I highly doubt this has happened to anyone else in the world.

Last year, I took a small gamble and bought a 1960s hand wound Seamaster 600 off of Catawiki. It didn’t keep time that accurate when it arrived but I had already factored that possibility in.

Whilst it was a gamble, I asked a local vintage watch shop to have a look and they didn’t have any doubt as to the genuinity of it. I had it fully serviced for approximately EUR 500 and initially it was smooth sailing all along. However, after a couple of weeks it started losing time so I brought it back. It turned out that the ratchet wheel screw was loose/lost it threads. They replaced it and then it ran well for a while.

Unfortunately, the same problem (losing time and not keeping consistent time after setting) occurred again and they had a look. Thing is: the seconds dial always keeps running accurately, but after setting, the minutes dial seems to only engage after approximately 8-10 minutes. After that, sometimes the watch keeps running behind for 10 minutes accurately. When you try to set it 10 minutes in advance, either of two things happens: the watch loses even more time and then starts running and sometimes it keeps running consistently 10 minutes in advance. It is as if it has its own will.

The shop where I had it serviced is very helpful and asked me to come bring it in as it is still under warranty. This would be the fourth time I bring it back. Now before I do that again I tried something else: I let the watch run out of kts power reserve (24-36 hours) then wound and set it again (normally I just wound it every morning). It runs nice and accurate right now.

Now my question would be: do any of you have similar experiences with watches from this era? I am just looking to see whether this is normal behavior or that the full service may have lacked something.

For completeness, its a 136.011, 611 cal. And one additional question: would you recommend winding it daily, or just waiting for it to run out of power and then completely wind it?

Sounds Like a loose canon Pinion. Do you feel resistance when Setting the Time or are the hands turning freely? But this is just a hobby watchmakers guess. I think the experts will answer soon

I do feel some resistance now (after I had set it after letting it run out of power). Funny thing is, it is running quite consistent now. Would it make sense to think that many partial winds (e.g. winding when only half or 3/4 of the power reserve is depleted) lead to the main spring becoming "lazy"? And that it is better to have it run out every now and then to keep it running accurately? I will in any event ask them to check the canon Pinion when I bring it in.

Thanks for the helpful replies and good to understand the mechanics! To answer your questions Erich: bringing it back after the service for the ratchet wheel was the first time, then second time for losing time again, then it was fine for quite some weeks and it lost time again and they fixed it again. And this would indeed be the third time bringing it back, well spotted. And indeed, vintage watch ownership is like this; a colleague of mine compared it with owning an older Italian sportsbike, which he happens to have 😉. Still enjoying the watch though!