1965 Hamilton Accumatic A-506 | Restoration

1965 Hamilton Accumatic A-506 | Restoration

The Hamilton Accumatic A-506 was made for eight years from 1965 through 1972 and featured a Swiss (ETA) made automatic 689A caliber movement.

The A-506 has a one-piece, or monocoque, case which means the first step in disassembly is to remove the crystal. The tool here is called a crystal lift and it squeezes the sides of the acrylic crystal with the brass fingers. 

This allows the crystal to be lifted out of the case and access to the dial and movement.

One-piece cases use split stems in order to be able to insert, and remove, the movement. This is the crown and the male half of the stem.

The inside of the one-piece case looks super clean, a good sign for sure.

The watch maker's side of the movement is also clean. The weighted rotor is what spins around to automatically wind the watch from the movement of the arm.

With the dial out of the way, the dial side of the movement is exposed. On the right side of the movement is the keyless works, the series of components that wind the watch and set the time.

On the other side of the movement, the female half of the stem is removed.

The train of wheels is now visible with the train wheel and barrel bridges removed.

Before removing the balance cock, the upper balance setting is removed by opening up the shock.

The shock is then closed to prevent damage during the cleaning process.

On the dial side, there is another shock protected jewel that can be difficult to remove. This best way I've found is to use a fine oiler to pry the shock loose, then grab the tiny cap jewel with a bit of rodico.

The automatic works is completely disassembled for cleaning.

After all the parts are cleaned and dried, reassembly begins as the hour and minute hands are relumed using a balance tack to hold them in place.

The pips on the hour markers are also relumed.

The movement completely reassembled and lubricated with the automatic works in place.

The handset is reinstalled and checked for clearance.

Using a jig to position the crystal lift properly, the crystal lift is used to squeeze the crystal so it can be refitted into the case.

After a quick initial regulation, this watch is running strong and will settle down over the next few days as it runs in.

This A-506 looks sharp on its stainless steel expansion bracelet.

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