1963 Thinline 4500 - Overhaul

In the late 1950's and 1960's Hamilton utilized a variety of Swiss-made movements that allowed them to produce a broad array of ultra-thin models.  Automatics were made as part of the Thin-o-matic line and manual winders were a part of the Thinline series.  These watches came in all sorts of shapes and sizes and in a variety of materials too.

On example of a stylish manual winder is the 1963 Thinline 4500.  It was produced for only two years.

The Thinline 4500 has a one-piece case with a 10K white gold filled bezel and an integrated stainless steel back.  The dial is accessed by removing the decorative faceted crystal.  The silver dial is accented with very thin black baton-styled hands that complement the watch's thin-style.

I recently overhauled a Thinline 4500, so I will show you how it goes.

Starting off, the watch was in very nice over all condition.

Behind the dial is a 17-jewel Swiss-made Hamilton 687 movement.  You can see the female portion of the two-piece stem that allows the movement to be pulled out the front.  The male portion is installed in the crown.

The case has no watchmakers marks inside the back, but there is one on the outside.  That would say that this watch has been overhauled at least once in it's 50 years.

Once it's all disassembled, everything gets cleaned and is set out to dry.

The first things to go back in are the pallet fork and then the four wheels, starting with the escape wheel and ending with the center wheel.

The train bridge incorporates all four wheels - so getting them all lined up can be tricky.  Fortunately since the wheels have very short arbors they're not as hard to line up as other four-wheel bridges like on the 748 movement.

Next in is the mainspring barrel and it's bridge.  If you look closely you may note that the click spring is missing.  The click is what you hear when you wind the watch and it engages the ratchet wheel (the larger of the two wheels) and keeps the mainspring from unwinding back through the stem / crown.

The click spring fell out in the ultrasonic cleaner.  It's not very large and care must be taken in putting it back - as click springs like to shoot out in any random direction if you're not careful.

Here it is, back installed.  So the ratchet wheel can go back in now.

With some tension re-applied to the mainspring, the next thing to go on is the balance assembly.  But first, the jewel in the balance bridge jewel gets a tiny droplet of oil.  This balance wheel is machine poised at the factory so there are no adjustment screws.  You can see tiny holes where ever-so-slight amounts of material have been removed to make sure the wheel and hair spring is properly balanced.

Flipping the movement over, the setting wheel and minute wheel go back on and everything is lubed with fresh grease.

On the timer, the watch started out running a couple of minutes fast but after a little tweaking to the regulator it's back to running great at 4 seconds fast per day.

In this shot you can see why they called this the Thinline series.

The dial goes back on and the movement is reinstalled in the case.  Then the hour and minute hands go on at 12:00 so they're assured to be lined up correctly thereafter.

The crystal is reinstalled along with a new black lizard strap and this watch is ready for wrist time