1954 Automatic K-500

About six years ago I did a post on a mystery watch that turned out to be an Automatic K-500  from 1954.  The K-500 was not cataloged but it did show up in a number of advertisements.

The K-500 is a very interesting model as it has several different dials and it's one of very few models that had a stainless case but gold dial markers and hands.

I recently had the opportunity to work on another K-500, this time with a black dial with a unique textured design.  As received, it was very beat up and in serious need of some TLC.

The case back is beefy can clearly marked Hamilton.

The inside of the case back is marked with 9959, the same model number as my other K-500 project.

Inside the case is a partial movement.  It's missing the automatic framework and rotor.  The first question is what caliber is this... a 658 or a 661?  One thing is for sure, this movement is wound tight - and that is very odd for an automatic, as an automatic is designed to wind continuously and once the mainspring is tight it will slip a little and allow the automatic to keep winding.

The precursor to the 661 was the 658.  It was only used in 1954 and for all intents and purposes it's the same as the 661 other than the design of the rotor and connection to the automatic framework.

The 661 rotor is held on with a unique switch design were you move a detent from one side to the other in order to free the rotor from the movement. 

The movement was secured to a movement ring by two screws.  One of them is broken, the screw head is broken in half and will need to be replaced.

The mainspring barrel is lumpy... I've never seen this before.  I suspect the cover was loose so a watchmaker added a bunch of dents to stretch it a little.  I'll clean it with the other parts but I suspect this barrel has been modified to use a manual-winding mainspring with a fixed end.

Everything is cleaned and dried.

I had to replace the barrel, as I suspected and the pallet fork as well, but now the movement is running with a good motion.

Based on the timer it's running a smidgen slow but it won't take much of a adjustment to speed the watch up.

There... running very clean and just a little fast.  The amplitude is a little low.  It may come up as things settle in and I'll have to see how long the watch runs on a full wind.

I decided to go with the 658 rotor and framework.  This movement is now back to the same outfit that it likely had when it left the Hamilton factory almost 70 years ago.

A new crystal and some fresh lume on the hands complete the restoration of this watch.  It now looks and runs much better.  Black dials are very hard to photograph.  The dial is by no means perfect but it looks very authentic.