1923 910 Pocket Watch in Franklin Case

Continuing my foray into watches I have stashed away in my workshop, I pulled out a 12 Sized dress pocket watch from 1923.  It appears to have a broken mainspring, as I can just wind and wind away to my heart's content.  The mainspring could also have simply come unattached from the arbor... we'll see.

In 1923 pocket watches were the dominant time piece for men.  In fact, if you wanted a wrist watch you had your choice of only one... but you could get it in sterling silver or 14K gold.

When it came to pocket watches you had a lot more of a selection.  They came in three sizes, 12 Size, 16 Size and 18 Size.  If you were a railroad man you'd need at least a 16 Size to meet the railroad specs, but there were a lot more requirements after that.  Generally speaking you'd need at least a 992 in 16 Size or the 940 in 18 Size.

The 12 Size was considered more of a dress watch for a man of distinction.  I always imagine a silver haired banker wearing a coat and vest with a chain going from a vest button on one end and a 12 Sized Hamilton watch in the vest pocket on the other end.

You had quite a few options to choose from and by this time, Hamilton sold dress watches complete and cased by Hamilton.  You could still purchase the larger 16 or 18 Size movements separately and have them cased by the jeweler you purchased from.

The entry-level dress pocket watch was the 910, followed by the 914, 900, and the cat daddy 920, which was reputed to be the most accurate 12 Size watch available in America.

Just for comparisons sake, here's the 1923 catalog descriptions for the 920 and the 910 models.  The 920 featured 23 jewels, a motor barrel (where the barrel was supported by jewels), solid gold jewel settings, solid gold train wheels, and a highly adjusted balance, among other features.  Plus it was cased in heavy solid gold cases.

On the other hand, the 910 was no slouch but it was more of a common man's watch.  It's jewels were set in simple brass chatons and it was offered in gold filled cases with 25 year warranties, so there was still a bit of gold in the case.

My project was is in the Franklin case.  It had a broken crystal but I placed a new one on for the photo.  You can see that it's cased in the green gold filled option.  You could choose from a variety of dials.

The case has a pop-off bezel and a hinged back cover with an integral hinged dust cover.  This one is nicely engraved with it's original owners initials, EHB or is it EBH?  I've seen it both ways.

This case is pretty dirty and the inside dust cover snaps onto the center of the case, as does the rear cover.  I've seen the inside dust cover used for presentations as well, but this one is untouched other than the Hamilton logo.

The movement inside appears to be in good shape.  The balance doesn't wobble so I'm hopeful it will work fine after a good cleaning and new mainspring is installed.

Two case screws secure the movement to the case and once they are removed the assembly can be pushed out the front (as long as the bezel is removed).  At this point I can start to disassemble it.  I know the mainspring has no tension to unwind.

I pull the hands and then unscrew the three dial foot screws on the side of the main plate that secure the dial in place,

Most dress pocket watches are negative-set (versus lever set).  That means that in their normal uncased position, springs inside the movement hold the clutch in the time-setting position.  

Inside the case pendant there is a part called the stem sleeve - it's what you feel release when you pull the crown out to set the time and it's what snaps hold when you push the crown back in.  

As shown below, there are a series of springs (levers) that hold the clutch in the setting position.  When you push the crown in, it overcomes these springs and moves the clutch into the winding position.  At that point when you turn the crown the watch can be wound.  

That's a really long way of saying the stem sleeve is what holds the watch in the winding position, if it gets worn out, the springs in the movement will push the crown out to the setting position and risk inadvertently changing the time.  For this reason, railroad watches were required to be lever set.  Negative set movements would not meet the standard.

Next I pull the balance so it doesn't risk damage and I can pull the two large screws that hold the winding and ratchet wheels.  The winding screw is reverse-threaded so it's righty-loosy to unscrew it - that's really important to know, because if you tried to turn it the other way, you could break it off.  All of the other screws are lefty-loosy.

Well, the mystery is solved, the mainspring is clearly broken.

While all the parts are being cleaned I will get out a new mainspring for installation in the barrel.

Everything is cleaned and inspected before being reassembled with fresh lubricants.

I need to put the train wheels in place before installing the train bridge, as once the bridge is in place the center wheel won't go in.  I'll also install the barrel bridge once the train bridge is on.

Once the train and barrel bridge is in place, I install the pallet fork and it's bridge.  At this point I can install the movement in the case so I can use the crown to wind up the mainspring.

Once the mainspring is wound, I can remove the movement from the case again and now it's ready for the balance to be installed.  I get it in place and the movement comes back to life.

It's running a little slow but otherwise looks okay.  I should be able to speed it up a bit.

There... it's good to go now.

I noticed a little smudge on the dial and when I went to wipe it with a cloth, I removed the Hamilton name and some of the seconds register... ugh!  I should have known better.  Fortunately I had another dial from a donor movement and was able to complete the restoration of this 102 year old Franklin.  I don't know who EHB is but I hope, somewhere, he'd be happy to see his watch working again.