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Saturday, January 28, 2017

1969 Mystery Model

It's been a while since I was stumped by a watch.

It was not unusual for Hamilton movements to outlast their original cases.  So you will often find Hamilton movements that have been recased.  They're not mystery models, they are jeweler-cased watches, often referred to as mules or frankens (like Frankenstine).

As a general rule, Hamilton marked the inside of their case backs with "Hamilton Watch Co. Lancaster PA".  So I use that as a guide for ensuring a watch is a legitimate model.  There are some exceptions though - but mostly from the 1930's with models with Keystone cases.  See the Turner for an example.

There is one model from the late 1960's that is also an exception to the rule - and that's the uncatalogued 1969 Liberty Coin.  This model is rumored to have been made partly to use up excess inventory of 770 movements when production in the US was discontinued.

I have seen a number of examples of another watch that I believe was produced under similar circumstances and I finally landed one.

I've seen this watch in both yellow and white.  It has a radial finished dial with diamond markers at 12, 3, 6 and 9.  It would be fair to presume that this watch would be part of the Lord Lancaster line.

It's a little unusual that the dial has 18 Jewels printed on the it.  That's not unheard of but it's often a sign of a franken.  However, the Liberty Coin says 22 jewels on it.

One thing I've observed when I've seen this model is the back of the case appears to be poorly crafted and pock marked.  Notice how the back says Hamilton on it - that's something frankens do not typically have.  But also notice the stamp isn't centered very well... that's not something you will typically see on Hamilton-produced watches.

This watch happened to have a Hamilton bracelet on it but it's not really appropriate for this style watch.  It just doesn't quite look right, as you'd probably agree.  So I'll save it for another watch someday.

Close observation of the case reveals that it's a two-piece design and a case knife will separate the bezel from the back with a little prying.

Without the bezel in the way, you can see the dial looks to be in good shape.  The inside of the case back looks as poorly crafted as the outside though.

The inside lacks any Hamilton Watch Co identification... I'd be concerned but the Liberty Coin is similarly marked.  Notice there is no serial number on the inside or out of the case.  It looks like this case back could use a little cleaning, I'm sure the movement is the same.

Turning the dial over, there's an 8/0 size 18 jewel 736 movement inside.  This movement replaced the 735 in the 1960's and offers a glucydur balance.  This is clearly a late 1960's watch.

Everything is cleaned and dried.  Now it's time for reassembly.

The reassembled movement is ticking away and appears to have good motion.  So it's off to the timer.

Uh oh, there's something definitely not right.  The 52 degrees alternates with the beat rate and the timer is thinking this should be a 19600 beats per hour beat rate.  I'll run it past the demagnetizer and reclean the hairspring, then see how it's doing.

Well, that's much better.  Good beat rate, good amplitude.  However, the beat error of 4.3ms is a bit high.  I prefer it to be under 3.0 and as close to zero as I can get it.  Adjusting the beat error on this style of balance is a very delicate process and it's very easy to goof up the hairspring if you're not careful.

Alright, now I'm down to 2.6ms.  I'll call it quits at that.  I could probably get it lower but why tempt fate?  A high beat error will cause a watch to stop a little sooner than a watch with a low beat error, but the overall time keeping is largely unaffected.

A quick tweak to the regulator slows the watch back down to a nice beat rate.  Notice the timer now says it's picking up an 18000 beats per hour rate - that's 5 ticks per second, just as it should be.

A fresh crystal and lizard strap completes the rejuvenation of this old Hamilton watch.  It looks fantastic from this perspective.

Of course, the back doesn't look much better.  However you don't see this side when it's on the wrist.  Now if only I could find out the real story behind this watch.  I suspect this model was produced to use up excess inventory of 736 movements - but that's just a guess at this point.



  1. I recently picked up this new in the box (including outer box) "Mystery Model" that is similar to yours. I have more pics available.