We can make almost any watch tick and keep good time when it’s left dial-up on a shelf, but not all watches can or should be adjusted to keep close time across several positions. Before getting started with adjustment, make sure you’re working on the right kind of watch.

Good Signs

For vintage watches, here are signs that a watch is capable of being adjusted to close time:

• at least 17 jewels for wrist watches
• at least 15 jewels for pocket watches
• a balance wheel whose rim has slotted screws that can be removed and replaced

These features make adjusting easier but aren’t necessary:

• an overcoiled hairspring
• a micrometer regulator
• removable cap jewels
• adjustable mean time screws (common for pocket watches)
• free-sprung, adjustable mass balances (rare for vintage American watches)

What Watches Aren’t Worth the Trouble?

Many watches aren’t worth the time and trouble to adjust. Avoid watches with these features:

• Pin pallet escapements. These were the cheap quartz watches of their day. They were not designed for positional timing. Jendritzki, in Watch Adjustment (p. 74), suggests a standard of 60-120 seconds between dial-up and pendant down. That’s pretty bad.
• Watches with fewer than 15 jewels. American companies made many charming 7 and 11 jewel pocket watches, but the pivots and bearings eventually grind down, making it hard to get a stable rate.
• Quirky escapements. It probably goes without saying, but dynamic poising methods designed for the classic lever escapement won’t get you far with your elegant Waltham with a cylinder escapement.
• Watches with serious flaws you’re unwilling to fix. In his book, de Carle puts the fear of the cleanliness gods into would-be adjusters. We can’t adjust watches in poor condition. If you’re not willing to replace cracked jewels or straighten bent pivots, the watch can’t be adjusted. It isn’t always laziness: rusty hairsprings, for example, are common in older watches that are otherwise in great shape, but not many are worth the time and expense of vibrating a new hairspring.
• Watches not designed for adjustment. If you can’t easily add or remove weight from a watch (or modify its relative weight for free-sprung watches), it isn’t designed for positional timing.

For example, here’s a watch I passed on. This Helvetia 830 is an interesting watch, but it has a cheap balance. There are screw-shaped weights around the balance, but they aren’t slotted screws. As a result, you could remove weight by filing or undercutting, but you couldn’t easily add weight with timing washers.

Likewise, this Gruen had potential. The Gruen 335 is a nice 21-jewel mechanism from a company that is under-appreciated by most collectors. Normally, it would have a quality slotted screw balance, but at some point someone swapped a cheap aftermarket balance with non-removable timing screws.

You’ll occasionally write off a watch as a lost cause. I recently picked up a Hamilton 987F that had clearly spent some time in a dark place. The balance beat at 19,800 rather than 18,000, so the hairspring had been vibrated to the wrong rate. The wheel was stuffed with huge timing washers, and the bridges look they were gouged by an anteater.

What Watches Could But Shouldn’t Be Adjusted?

For restoration work, you might not want to modify the watch in ways necessary for adjustment. Adding timing washers, filing weight from screws, and polishing and reshaping balance pivots might not be appropriate when your goal is historic preservation rather than getting a watch ready for daily use.

For example, my grandfather’s Waltham 1883 keeps deplorable time across positions. I cleaned and oiled it so that it could run without harm, but I didn’t adjust it. It wouldn’t be hard to adjust, but I want to leave as it was when my grandpa owned it.