Cal. 321 accuracy question…

I have a cal 321 Speedmaster, that is running dial up, crown left, and crown down with a high rate in all positions (about 4 minutes fast), and with a concomitant low amplitude (180’s).

I tried to demagnetize three times with no change. Any ideas what could cause this specific anomaly? Thanks.

When was it last serviced?

It’s complicated. The watch was very lightly used over the years, and the balance complete was removed and used for a better watch.

Then, I found an NOS balance complete for the watch, and my local watchmaker installed it, and supposedly lubricated “ all the essential parts.”

So, no doubt it needs a full service, but just trying to get a handle, if possible, on what could cause this particular set of abnormalities.

A new mainspring is probably needed but I don’t think you can dodge a full service really. Changing bits here and there is likely false economy.

Even if the “essential parts” are lubricated, I assume there’s still dirt, dried up oils and contaminants impacting the performance of the movement.
Would seem likely to me it just needs a good service.

Im sure that’s true, and it may be too esoteric for anyone who isn’t an experienced watchmaker, but I was just trying to get a sense (since the findings are position consistent) what the likely cause could be: the balance wheel, other adjacent parts, etc.

Backyard supposedly watchmaker is probable the cause. 😗


A few of the reasons why a watch may be fast:
• The movement requires professional service.
• The balance spring has been magnetized (this may cause the watch to go fast by as much as several hours per day).
• The watch has sustained some significant impact and caused the last winding in the spring to skip forward.
• The spring is clinging together.
• An impact on the watch altered the spring’s key.


And some causes to make a watch slow:
• The movement needs to be professionally serviced.
• An impact caused the dial to move and create binding on the digits (this is becoming more frequent lately)
• An impact altered the spring’s key.

Anytime when your watch is running fast or slow, it is advisable to see a watchmaker and let them diagnose the cause for the inaccuracy.