When adjusting, the first positions we tackle are the horizontal ones: dial up (DU) and dial down (DD). For many watches, getting DU and DD to agree is most of the work in adjusting. Many, many things can cause differences between the DU and DD positions, but some are more likely than others.
Scraping Off the Crust
Dirty pivots are one of the most common causes. Vintage watches are usually dirty, sometimes grimy, and occasionally nasty. A watch might not have been cleaned since FDR was president. Dust mixes with the old oil and calcifies into a crusty coating on the jewel and pivots.
If one pivot is dirtier than the other, the DU and DD positions will involve different friction levels. This will affect the watch’s amplitude and hence rates. The difference in grime needn’t be great to have a big effect on accuracy. Much of the time, simply cleaning the pivots is enough to line up the DU/DD rates.
The first level of cleaning is the usual one. Presumably, the balance assembly is cleaned and rinsed in watch cleaning solutions. Rubbing the pivots in pithwood is often enough to scrub the pivots clean.
The Next Level
But sometimes we need to kick it up a notch. Crusty pivots, like crusty jewels, need a thorough scrubbing. In The Watch Repairer’s Manual (4th ed., 156-157), Fried describes a useful method for scrubbing pivots to a clean and shiny polish without removing metal or changing a pivot’s shape.
For materials, you’ll need some inexpensive oil, some soft wood sticks, and some jeweler’s rouge. For oil, I use a big bottle of basic clock oil.
For sticks, pegwood works well. But it’s hard to beat a huge bag of craft store “Woodsies” sticks, should you need to clean 750 balance staffs but have only $4 in your wallet.
Jeweler’s rouge is used to polish precious metals like gold without cutting away material. This makes it safe to use when you want to polish the staff without changing the pivots’ shape. You can get jeweler’s rouge in all the usual places; I use Dialux Red.
Fried says to wipe some oil on the stick and then rub the stick against a clean side of the rouge bar—that is, not the side you smear against your buffing wheels. (I set aside a container of clean shavings for this purpose.) Once you’ve charged the stick with the rouge, you’re ready to go.
The stick is soft enough so that the pivot can get embedded in it safely, allowing a thorough polishing of the tip and sides.
To mount the balance, you can place it in a balloon chuck in a lathe or set it in a pivot polisher. But you can also simply freehand it: the wood is soft, and you won’t reshape the pivot with rouge on a stick. Afterward, of course, the balance assembly should be cleaned to remove any residue.
This approach to cleaning works wonders. The pivots will have a dazzling shine, and your DU/DD issues might be solved.
The Illinois 405 pocket watch we adjusted, for example, had a DU/DD difference of around 9 seconds. After cleaning the pivots with this method, the difference was closed to 2 or 3 seconds. Likewise, our Hamilton 747 “Fulton” wristwatch went from a difference of around 20 seconds to around 2 seconds after pivot cleaning. It’s worth a few minutes during the normal course of cleaning an old watch.
But if this doesn’t align your DU and DD rates, then you’ll need to look for one of the many other likely causes.