Part 1: Hamilton Myron - caliber 980 - Disassembly

My brave, trusting sister sent me the Hamilton Myron she found on eBay as my first real victim project.  She had worn the watch for a few weeks before finding that though it kept decent time, it would run only about 8-10 hours on a full wind. As received it was actually in very nice shape cosmetically.

The case pries open through the back, which is stamped with the serial number S387212 and 10K GOLD FILLED.  The dial is very clean, and really does not need any help from me.

The caliber 980 movement (SN G509286) seems to be in good shape.  According to this link it dates to 1946.  This is a common movement and replacement parts are easy to find.  One thing that stands out is that the adjustment pointer is set well past "S", which makes me wonder if something could be jacked up with the balance or hairspring.  Reportedly, it kept pretty good time, so I am hoping a good clean and lube will bring it more into regulation.

My new/old hand lifter makes short work of the hands, then the dial is removed by loosening two retention screws in either edge of the plate and prying gently.

(Pretend I have gloves on in the second photo and don't tell Sis.)  

The dial side of the movement is a little grungy with some yellowish spoo (watchmaker terminology for congealed lubricant) at the top in this photo and some blackish stuff at bottom right.  

Now the fun begins.  Flip the movement dial side down and unscrew stuff, beginning with the balance.  This is removed first and returned last because it is fragile and can be damaged during the rest of the disassembly/reassembly process.  I am using a legal pad as my work surface and taking notes as I go to help me reverse the process and not forget anything.

Continuing to remove screws and parts, I manage to remove the ratchet wheel without stripping the left-handed screw that ruined my previous venture.  (He can be taught.)  

Next, the train wheels and barrel come out.  

The barrel houses the mainspring which stores the energy to power the watch movement.

Sure enough, the mainspring is tired after about 70 years.  A fresh mainspring will uncoil to a bigger "?" shape, so this one needs to be replaced.

Last in disassembly is removing the winding and setting mechanism including the stem and other parts that function when one pops the crown in and out to set the time and wind the watch.  Here are all the movement parts laid out in order of removal, L-R, top-bottom.

So far, so good.  Nothing broken, nothing lost.

Next up...

• Cleaning movement parts.
• Lubricating all jewels and moving parts.
• Greasing and installing the new mainspring.
• Reassembling the movement.
• Adjusting the timing.
• Assemble dial, hands, etc.
• Fitting a new crystal to the bezel.
• Polish the bezel and case.
• Fitting a new lizard strap.

Update: 21-May-2015

I received the new mainspring and crystal for Myron.