1977 Thin-o-matic

The last post I did happened to be an early Thin-o-matic model.  By chance, my next project was also a Thin-o-matic, but I think it was a Thin-o-matic in name only.

It's from "the dark ages" of Hamilton watches - the late 1970s, which extended into the 1980s.  A lot was going on during that period and the company that was once the Hamilton Watch Company in Lancaster PA, became the Hamilton Watch Company, a division of whatever holding company owned them, eventually landing on the Swatch Group.  Concurrently, watch technology quickly evolved too and a good portion of Hamilton's model lineup in the 1970s was electronic watches like LEDs and LCD models.

My project watch was an award for an employee of Chevron.  You'll see a lot of watches in the wild with the Chevron logo.  Like Hamilton, Chevron had several predecessors incliding; Star Oil, Pacific Coast, and Standard Oil.

My project is a nice watch, cased in solid 14K yellow gold.  The dial appears to be a classic Hamilton dial, sterling silver with solid gold numerals and markers.  The Chevron logo dominates the top portion of the dial and Hamilton with Thin-o-matic is printed on the bottom half.

Although the dial says Thin-o-matic, this is not a very thin case.  The model number is 978077.  I believe the last two digits are the year of the model.  The case back is engraved with a presentation from 1981 from Standard Oil Company.

The watch opens through the crystal.  Once the crystal is removed, I can lift the dial and movement ou the front.

The case has a deep back, with no mention of Lancaster PA by this time. The number within is unique to this watch and means nothing to anyone other than the case maker, B&A.

The power plant behind the dial is a Hamilton 835 movement.  This is based on an ETA 2871.  I expected to see a white Buren micro-rotor behind the dial, being a Thin-o-matic, but I guess those days were behind them when this watch was made.

The female-side of the two-piece stem looks odd to me, like the old CLD-style female stem.  Turns out it was just loaded with dirt.  Once it was cleaned it looked normal.

By this time period, dial foot screws were replaced my dial clamps, J shaped levers that rotate to pinch the dial feet in place.  Once they are rotated outward, the dial can lift off.

The dial side of the main plate is rather crude looking to my eye... it's sort of Jack Webb of Dragnet theme... "just the facts".  A single screw holds the bridge for the minute wheel and setting wheel.  The ring around the perimeter is a spacer that supports the dial and will lift off.

A single screw holds the oscillating weight in place and once it's out of the way, I can remove the framework that supports it.

At this point this is now just a manual winding watch.  You may be able to see the strong family resemblance between this movement and the earlier ETA calibers like the 688.  There are some differences, of course, but the basics are all the same.

The case has short lugs and will benefit from curved spring bars when it's time to mount a strap.

Everything is cleaned and ready to be reassembled.  I found the little bent golden wire at the top in my cleaning solution... I wonder where it goes?

Aha!  It took me a while but I realized that the bent wire was part of the click that enables winding.  This movement uses an integrated click and spring and the spring part broke off.  Fortunately I have a donor part to use.  You can see on the left what it's supposed to look like.

With a functioning click, I can wind the watch and then install the balance.  It's now ticking away with a brisk motion.  This movement has a 21600 beat per hour rate - a lot faster than the typical 18000 BPH rate of most vintage watches.

Not too shabby.  I can slow it down easily enough.

And voila!  The movement is now running right on the money.

A new crystal and a fresh strap complete the restoration of this elegant almost 50 year old watch.  I relumed the hands and dial so it will glow in the dark again too.  Looks pretty good, don't you think?