Positional Errors, What Do You Think Is Acceptable?

[Men]

Hi,

Just wandering what you think is acceptable on positional errors in old watches. Where do you draw the line?

Shoot!

Men

[matabog]

from an amateur point of view, a minute is the limit. 30 sec is confortable , 20 sec is great. Beyond that it is impressive.

[Men]

And from a prof's point of view?

[ChrisN]

I'm not a professional but use the Omega requirements for a 565 for any non chronometer movement. I can show you a COSC spec if you're interested in that as well. Here's a sheet I print and use.

These are not known for brilliant amplitude but this is not bad. I usually test all six positions but for some reason, I didn't here. I was happy enough. These are only tested in these three positions anyway. COSC in five and 12H only used for you.

You should test at full wind (0H) and one day later (24H). Obviously, don't wear it if its an auto! For the 0H, I usually fully wind and leave it for 30 minutes before testing. As matabog said, basically thirty seconds is within spec. This one is so far in it would likely meet COSC spec. Lift angle and power reserve are calibre specific but the rest are good usable values in my opinion for a lever escapement. Target rate is +8 for these but I usually set them a bit slower and check after use.

Hope this helps, Chris

[Men]

For me 30 sec. is not acceptable. Personally I always aim for +8 sec which is often a challenge in very old watches and If you want to stay commercial on the good side.

[ChrisN]

It sounds like you are a professional? I'm new here so are not sure who is who. I had assumed you were an amateur and didn't want to be too discouraging.

Are you saying that you aim for an 8 second variation across 5 positions on any watch? So, for something like an Omega 565, it is possible to get there. But a cheap fifties/sixties movement? I'm not being argumentative just trying to make sense of what you are saying. Even if you're using everything including dynamic balancing surely you're limited by the basic quality?

Perhaps you could give us some more information?

Cheers, Chris

[agoldflam]

In my opinion it ultimately depends the condition of the movement and what damaged parts you can replace/repair. The more you can, the better delta you will achieve.

For example, balance staff, cap jewels, mainspring obviously, pallet fork jewels, wheels, just to put a few out there.

If all can be replaced or repaired then then the original manufacture tolerances can be met and sometimes surpassed, temporarily.

Simply put, vintage: 20 sec 0H 30 sec 24H, 6 positions, daily rate between +1 to +10 seconds.

Modern watches stick to the tech docs and stay within spec but mostly under 10 second delta 6 positions at 0H and 24H and daily rate +2 to +6 seconds, that's acceptable to me!

Through watchmaking I restore connections in people's lives!

[Men]

This is exactly my point. Not getting the parts where do you stop... where do you draw the line in vintage going back to the customer presenting a huge bill because of time consuming parts creation are declare it acceptable because no parts are available to get the +1 - +10.

[agoldflam]

I think it's up to the customer and what they want, sometimes it's enough that the watch just ticks and that's a quick enough fix that leaves everyone satisfied, the challenging ones are when someone has an unreasonable request and them some education is necessary

Through watchmaking I restore connections in people's lives!