Adjusting a Feisty 1919 Illinois 16s 305 Pocket Watch to 5 Positions and Restoring its Case

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I’ve been trying to do fewer Illinois pocket watches, and I did manage to stray into some offbeat Russian watches, but the heart wants what it wants. That’s why we have another Illinois watch this week—in this case, a 16-size, 17 jewel Grade 305 from 1919.

This is a workhorse Illinois model. It isn’t a fancy 19+ jewel grade, like a Bunn or Bunn Special, but it is nevertheless an elegant watch. Like all Illinois watches from their golden period, this watch was designed for precision. It has a micrometer regulator, mean-time screws, and an overcoil hairspring.

Illinois brought a strong sense of craft to their watches. Check out the decoration on the bottom of the plate.

Most of this would be concealed when the watch is assembled. Notice in particular the mirror polish on the side of the main bridge. The mirror-polished edge is both concealed by the case and by the dust band, so an owner would never see it.

Check out the top of the mainspring barrel.

The top is nicely decorated but completely hidden when the watch is assembled.

This watch came from eBay in fair shape. It didn’t run, the crystal was scratched, and the case was missing a bow. As usual, the watch was stripped down, cleaned, and reassembled, with the usual visit to the demagnetizer.

The main faults were a broken blue-steel mainspring and a popped safety pinion, both easy fixes. This watch takes a 47315 mainspring if you’re working on one.

Adjusting the Watch

The watch started right up with a low beat error and excellent amplitude. The rates were only very slightly wavy, so this was running true to form for an Illinois watch. After it ran for a few days, I had a look at its rates in all 6 positions.

Not bad, but not great. It should be easy to improve on this. The DU and DD positions are the same, which is always a nice start. The biggest flaw is the large difference between the DU and PU positions. These are the main 2 positions for a pocket watch. We’d like all 6 to be close, but DU and PU must be close for the watch to keep good time in practice.

I could tell that someone had tried to adjust this watch before. A couple of the timing screws looked a bit worse for wear.

One of them (shown in the picture) had a big timing washer under it but had been undercut as well. That’s a classic sign of adjusting gone awry. Several of the screws look scraped and filed, but nothing too bad.

In some posts I give a step by step, blow by blow account of the adjusting process, which is intended to help people new to adjusting see how to think through the process.

For this post, I’ll focus on an issue that hasn’t popped up yet in a post: how do you do dynamic poising for a watch that won’t run well at low amplitude?

Dynamic poising is “dynamic” because we’re evaluating the balance wheel’s poise when it is in motion and interacting with the other components of the watch. As we’ve described in our how-to series, we can find the heavy spot on the balance wheel by running it at low amplitude, around 140-160 degrees.

But some watches don’t run well at low amplitude, and this makes dynamic poising hard. One kind of watch is just too noisy and wavy when the amplitude is low and the balance wheel lacks its usual velocity and momentum. When the rates are wavy like that, it’s hard to pin down the heavy spot.

This Illinois was another kind: a feisty watch. Some watches, usually quality pocket watches with new mainsprings, won’t run at a low enough amplitude. After a few clicks of winding, they’re off and running at 170+ degrees.

Normally, we love high amplitude in a watch, but such high amplitude from the get-go will drive an adjuster to madness. If you can’t measure the rates reliably at around 150 degrees, you can’t do dynamic poising.

This Illinois was vexing. With only a couple clicks of wind, the traces were too erratic and wavy, but with not too many clicks more, the amplitude was too high. Grrr… I occasionally have to remind myself that I work on watches because I enjoy it.

In this situation, you need some trial and error. Starting with the watch at rest, slowly wind it, 2 clicks at a time, and observe the watch’s amplitude. Once you have counted the number of clicks that yields clean traces yet also low enough amplitude, remember that number. During each round of poising, wind it to exactly that number. This won’t be perfect—the number of clicks can vary based on the watch’s position—but it’s a solid method.

After perhaps 8 to 10 irksome rounds, the watch ended up running nicely. Here’s a chart of the rates:

The DU and PU difference is certainly much improved.

This is more of a 5-position than 6-position adjustment. The PD position (the 6th position for a pocket watch) was stubborn for this watch. These old pocket watches were designed to throw the largest error into the 6th position (via the pinning point of the hairspring on the collet), and sometimes it is hard to sand down.

Here are the timing traces when the the watch is dial up. Note the good amplitude and low beat error.

And here it is pendant up.

Cleaning the Case

With the movement ticking away nicely, it was time to work on the case. This watch had a gold-filled case with some flaws.

  • It had a scratched and nicked plastic crystal
  • The case was grimy, scuffed, and tarnished
  • The crown is too small and cheap-looking
  • The bow was missing, so there was no way to carry the watch

Despite the swirls and scuffs, the gold-filled case was in good shape—just the usual wear that a watch gets when used. Here’s a “before” picture.

Gold-filled cases have a thick layer of gold, so they can be gently and carefully polished. They key is to use low pressure along with “low cut” buffing compounds. For this case, I first used Menzerna’s pink compound followed by Menzerna’s yellow compound.

The polishing made a big difference. You can still see scratches, but it’s unwise to try to buff those completely out of a gold-filled case.

It looks sleek and shiny.

Next up, a new crystal. A gentlemanly watch like this deserves a glass crystal, so I raided my stash of crystals to see if I have one that fits.

Measuring bezels and crystals is nearly hopeless for old watches. You need to go old-school: sort through the crystals and try ascending sizes until you find one that fits. The dimensional tolerances for crystals weren’t that fine back then.

This bezel took a 18 6/16 crystal, stated in the ever-irksome ligne scale. The new crystal looks great. It is thin and has a low profile. Glass crystals are set with UV glue, which dries clear and bonds tight.

Adjusting the Crown, Winding Stem, & Bow

And on to the rest of the case. I didn’t like the crown, which was obviously a cheap replacement intended for a much smaller watch. I sifted through my stash of crowns and found a nice gold-filled one that matched the case much better.

If you grip the square stem with small jeweler’s pliers, the crown will unscrew easily.

Removing the crown gave me a chance to adjust the depth of the winding stem. This watch would wind normally, but the hand-setting was irksome. The crown would feel loose and floppy when pulled out, and the hands wouldn’t move unless the crown was slightly pushed in.

This is a classic sign that the sleeve that holds the stem needs to be adjusted.

The sleeve screws into the neck of the case and holds the stem. Over time, with the pressure of setting and winding, the sleeve can get out of position.

Notice that the inside of the case neck is threaded. Screwing the sleeve in more deeply will make the stem engage at the right depth, so the hands should set normally without a lot of slack and play in the crown and stem.

For this, we need a sleeve wrench, which looks something like this.

Notches on the prong’s side fit into the slots in the sleeve, much like a screwdriver blade would. But because the stem is in the way, a screwdriver blade wouldn’t work. The hollow tube allows the wrench to fit over the stem so that the slots an engage with the sleeve, allowing it to be twisted. A few twists and the winding and setting was perfect.

As for the bow, I rummaged through my stash of bows and found a nice one that, after some polishing with the flex shaft, suits the watch nicely.

You can see how the inner diameter between the bow’s ends is much smaller than the diameter on the case. The bow has to be “opened” under tension so it can snap onto the case snugly.

To open a bow, you use a kind of pliers called…wait for it…bow-opening pliers. Squeezing the handles spreads open the bow, which is then slipped onto the case.

Easy-peasy, but incredibly hard and frustrating without the right tool.

Wrapping Up

And here’s the end result—a sharp watch that is ticking away happily. I like the double-sunk dial (with a small “character chip”) and the blue Breguet-style moon hands.

But I have a lot of Illinois watches around the house, so this one will go back into the stream. Fare thee well, old fellow.