On a work order, COA means clean, oil, and adjust. On a good bench it is the standard overhaul for a mechanical watch that is worth running.
- Diagnosis. Does it wind? Does it run? Is the balance free? Is rust already a problem? This is when you hear “this one is not worth a full service” if the parts or the case gold are the only value.
- Disassembly and clean. The movement comes apart. Old oil, dirt, and residue come off in a proper clean. A squirt of oil onto a dirty train is not a clean.
- Inspection and parts. Pivots, jewels, the mainspring, the escapement. Worn or broken pieces get replaced when parts exist. This is the line between a COA and a restoration.
- Oil. Fresh lubricant in the right places and amounts. Too much oil migrates and collects dust. Too little and you are back in a year.
- Adjust / time. The watch is put in beat and regulated. On a better grade that includes checking more than one position. “Runs on the bench” is not the same as “keeps usable time on the body or in the pocket.”
That is why a COA takes days on the calendar even when the bench time is a few hours: cleaning cycles, drying, oil, and a running test. A 3-month warranty is the watchmaker saying the job was this process, not a dip.
Estimates for this work are free at The Good Old Times. If the honest advice is to leave it alone, you still do not pay for the estimate.
After assembly the watch should run on the bench long enough to show that the oil went where it belongs and the escapement is not a lucky start. That is the “adjust” people forget: not only moving a regulator pin, but confirming the watch is in beat and not failing in one position. A railroad grade deserves that check. A 7-jewel deserves an honest version of it too, or an honest refusal.
When you collect the watch, you should be able to ask what was replaced and what was only cleaned. A mainspring change belongs on the ticket. So does “no parts, clean and oil only.” That record is the next owner’s service history. It is also why a warranty can exist. A fog of oil under the cock is not a history.
Have a pocket watch that needs attention? The Good Old Times offers
free, no-fee service estimates (no charge if you decide not to proceed), local drop-off in
Mississauga by appointment, and Canada-wide service by mail — every repair backed by a
3-month warranty. Get a free estimate →
Also browse: fully serviced watches for sale ·
pocket watch guides (Collector’s Corner).