Here's a nice example of an overhaul I recently did of a 1955 Hamilton Samson. These 1950's watches are really cool in my opinion and represent the turning point in US-made wristwatches where most manufacturers transitioned to Swiss-made movements in this time period. Hamilton maintained a mix of US and Swiss movements until their sale to the Swatch Group in 1969.
This model used the 17J US-made 747 model (later replaced by the 730).
It arrived a little beat up and in need of some tender loving care.
This model features a very small crown that tucks into the case a little bit. It's pretty worn and will need to be replaced as it's very hard to wind when it's this smooth.
With the back removed you can see the movement is in good shape and pretty clean. Even a clean watch that works fine should be serviced if you don't know it's service history. The oils inside will evaporate and without oil the delicate parts will wear out.
You have to remove the stem and crown (the crown attaches to the stem and the stem winds the watch) in order to pull the movement from the case. You can see the stem and crown in the upper right of the shot below.
Without a crystal, the dial and hands look pretty good and consistent with a 50 year old watch. It has an interesting rose-colored patina so I won't try to clean it.
I put the stem and crown back into the movement to hold the internal parts while I disassemble the watch. I also need it to help back off any mainspring tension that might still be lingering in the watch.
With the mainspring tension backed off, the watch is disassembled screw-by-screw, until all of the parts are completely removed and organized for cleaning.
Everything goes into an ultrasonic cleaner except the dial, hands and the balance assembly - which I treat very carefully.
Once everything is cleaned and dried, I oil every jewel and it all goes back together in the reverse order that I took it apart.
I like the 747 movement - it's very easy to reassemble. Two bridges cover the gear train and getting two pivots to line up is way easier than the three or four pivots other movements often involve. It has to all go back together smoothly... "it just fits". Any resistance at all and something's not lined up. Force is not an option here.
Here the watch is pretty much back together except the balance assembly - that always goes on last.
On the front of the watch there are some more places that lubrication is needed before the dial and hands go back on. The set spring yoke is removed to provide access.
An finally it's all back together and ready for the dial to go back on.
With the dial back on, it's flipped back over and the balance assembly is reinstalled. You can see it happily spinning away in a coat of fresh oil.
Put it all back in the freshly polished case with a nice Teju strap on it and it's ready for another 50 years of life. The crystal buffed up pretty well but there's a small crack at the 11 marker so I'll replace it before it goes into the rotation for wear.