Usually I buy parts to fit a broken watch, but other times I buy broken watches to fit my supply of parts. After working on the Elgin 315 we saw a while back I had a spare balance staff and mainspring for a 12-size Elgin, so I was on the hunt for a battered watch.

For better or worse, battered Elgin pocket watches are not hard to find. Here’s a charming old watch that fit the bill: a 12-size, 15 jewel Elgin 315 from 1921, according to Pocket Watch Database.

I love the octagon case—we need to start bringing that trend back. It’s a 14K gold-filled “snap on” case.

The inside of the case back has some deep scratches from someone running a gold test on it to see if it is solid gold.

“Why,” you might ask, “would someone do these defacing scratch tests when the case is clearly marked as gold filled?” Some miscreant scratched out “gold filled” with rough, horizontal lines in an inept attempt to pass off the case as solid gold. That won’t fool anyone. I hope the fellow was embarrassed when he brought this to the coin shop or pawn shop and tried to argue it was solid.

The dial is a metal dial with 1920s-style numbers and hands. It looks great with age-appropriate patina and toning.

These metal dials have a nice frosted finish. They represent the slow evolution of dials from the classic porcelain pocket watch dial to the metal dials that would become standard in wristwatches.

But these frosted dials require care when handling them and inserting and removing the hands. It’s easy to disrupt the finish and create shiny spots and scratches. Here are some signs of careless hand insertion and removal.

The movement has 15 jewels and some nice features that foster accurate timekeeping.

I especially like the regulator system used in these old Elgins. The regulator arms sits inside a pinion that can travel along the curved, threaded rod. It’s easy to make tiny, fine adjustments without putting a screwdriver near the hairspring.

This movement has the usual gunk and grime of an old, forgotten pocket watch. Some of the oil congealed and hardened into small pebbles. Have a look at the black rock near the escape wheel—it’s a hard pebble of old oil and grime. When people say “Don’t run an old pocket watch before cleaning it,” this is what they have in mind. The old oil will mix with dust and shavings to create abrasive particles that will grind away at the parts.

Here’s the old, tired blue steel mainspring. The blued springs are charming but wholly unsuited for a watch you intend to use. A snapped mainspring can cause a lot of damage to a gear train.

White alloy mainsprings are easy to find for Elgin watches. Here’s the spring this watch needs if you’re working on one.

The shift from blue steel to white alloy mainsprings was one of the great advances in watchmaking. I have run across one or two white alloy mainsprings that were “set” in coiled form, but they do seem to last forever, however long that is these days.

As for damaged parts, this watch must have received a huge jolt, probably a fall from a great height. It has all the signs. First, the balance staff is broken—the lower pivot is snapped off.

The roller jewel has chips and cracks. I don’t often see this, but when a watch is dropped, the jewel can bang against the pallet fork. It will have to be replaced.

And finally, the lower balance hole jewel (on the right) is cracked. When a balance staff is broken, a cracked jewel is usually not far behind.

The weirdest flaw, though, was one of the jewel screws for the upper balance cap jewel. At first, I couldn’t figure out why there were lines gouged into the bridge. It turns out that someone did some bad, bad watchmaking with this watch. After stripping the screw, someone tried to gouge the bridge so that the soft metal would form a small lip over the screw, holding it in place.

The hole is badly deformed. There was glue residue, so someone tried to glue the screw in place, too. Notice how the cylindrical hole for the jewels has lost its shape. More worrisome, the balance hole jewel sits in a thin rim, a lip that holds the setting. That lip is obviously deformed, causing the jewels to tilt at an angle instead of seating flat.

The hole was reshaped using cylindrical punches, which forced the hole back to its original shape and reinforced the lip. This process forced the material back toward the screw hole. I suspected that if the cylindrical jewel hole is proper then the screw will be okay. When the jewels are reinserted, a deeper screw can catch some of the intact threads near the bottom of the screw hole and, much like a thread chaser, reinstate the screw threads.

I have a stash of jewel screws I picked up as part of a lot of random stuff on eBay a long time ago. I’m looking for a screw that’s slightly longer and wider, and I found a few candidates.

I picked a screw that was blued so it would stand out. This will be a signal to whoever works on this watch next that each jewel screw is mated to a particular hole.

After the repairs and a good scrubbing, the watch came to life and started ticking away merrily. It got the usual demagnetizing and then a couple days of running for the oils and mainspring to settle in.

Adjusting the Movement

Even Elgin’s lower-grade movements are capable of good timekeeping. They made fine watches with excellent quality control. For this watch, we’ll aim for a solid 3-position adjustment instead of 5 or 6 positions. The watch ticks at excellent amplitude in all 6 positions, but the timing machine reveals that the rates are slightly unstable. They drift up and down around +/- 8 seconds over a several minute span, with no apparent cause (e.g., a bent pivot or chipped jewel). When a watch has wavy traces or unstable rates, you can’t attain really tight precision.

But for this watch, which is running pretty well, we can nevertheless make it much more precise than it currently is. It won’t run like a Rolex, but it can leave my workbench much better than it arrived, and it will keep great time in everyday use.

Here are the starting rates at full wind. The watch is running very fast, but this looks like something we can work with.

First, the horizontal rates—dial up and dial down—are close together, so we can avoid the often complicated step of aligning DU and DD.

Second, the rates in the 3 main pocket watch positions—DU, DD, and PU—are reasonably close. It shouldn’t be too hard to make this watch much more accurate than it is in the context of its condition.

To start off, as we explain in the dynamic poising tutorial, we run the watch in all 8 vertical positions at low amplitude, around 140-160 degrees. This reveals where the heaviest spot on the balance wheel is located.

For this little Elgin, the fastest rate at low amplitude was in the pendant down position.

This means that the heavy spot is directly below the balance wheel in the PU position, and naturally the lightest spot is directly above the balance wheel. The lightest spot happens to be directly under the regulator arm.

Because the watch is running fast, we should adjust it by adding weight to it. This will improve the poise of the balance wheel while also slowing down the watch. I placed a timing washer under the screw at the light spot, and this was a definite improvement.

All the rates are closer together than before, but the gap between the DU/DD positions and the PU position is still a bit larger than I’d like. A difference of 14 seconds isn’t bad for a 15-jewel watch, but we could get it tighter.

After a couple more rounds of experimenting with different sizes of timing washers, we ended up in a good spot.

The 3 main positions are all quite close, with a maximum differences of 6 seconds. And the remaining positions are really pretty good, too.

Keep in mind that the rates are slightly unstable, so these are averages that the watch drifts around. That +14 PU is anywhere from around +6 to +22 is you observed it over 5 minutes. If the rates were dead stable, we could further adjust the watch to very tight limits.

I’ll slightly move the regulator to set the watch near zero dial-up and call it a day.

Cleaning the Case

This snap-together case got a long soak in the heated ultrasonic cleaner. I run the ultrasonic fairly hot, around 140 degrees, and it easily removes all the grime. Without any polishing, the case already looks much better.

Then a light polishing with Menzerna’s final finish compounds (yellow and white) brought out the shine.

This case came with a glass crystal. A few scuffs and scratches on a glass crystal give a pocket watch character and a vintage feel, but this crystal is too far gone. It has that “sliding around in a drawer for decades” look to it.

I have a plastic crystal on hand that fits perfectly. Plastic crystals are less “age appropriate” but are the more practical choice for watches that someone intends to carry day in and day out.

When casing up the watch, a closer look at the hands showed some unusual scrapes.

These look like tooling marks, probably from an inept attempt to polish them. It is what it is. Clearly, someone with bad skills or low standards worked on this watch long ago, and it’s part of the history of this little timepiece.

Wrapping Up

And here we have it, all patched up and ready for service. The octagon case and dial are about as 1920s as pocket watches get.

I think 12-size pocket watches have a lot of charm. They’re small enough to fit into a pocket but large enough to handle, read, and show off to your pals.