hi all,
notice anything different about this model 21 chronometer?
fred

dial side

...Jim like 'bare bones' model... ...no idea other than the variable balance screws...thanks for showing it...Jim want to see more...

want a hint??
in the picture of the movement look real close at the center shaft.

Roller bearings?? This is cool!!

close phil,
this is actually test unit # 4 from my dads military collection. the hamilton labs tried this unit with ball bearings instead of bushing or jewels on the shafts. even the winding gear shaft has a pretty hefty ball bearing. this is the only hamilton model 21 ball bearing version known to exist. additional pictures are enclosed.
enjoy.
fred

close up of the dial ( which was originally cut out at the factory for display purposes )

movement close up showing some of the bearings

Fred,
Thanks for the interesting story on this watch. Now that we all know, it is even more cool!!!

Fred,
That is really a unique piece of engineering!, what was the goal of having the rollers?, were they aimed for use under special environment conditions?, it is intriguing me!

best guess would be that hamilton was looking for better accuracy and lower maintenance, especially maintenance, since the chronometers had to be dis-assembled, cleaned and timed at regular intervals.
fred

Now,How much of this chronometer?

what a treasure, to even get to see such a thing,the Holy Grail of American chronometers for sure and it shows Hamilton for the innovators and practical inventors and builders that they were ,and the whole world knows that their accomplishments in wartime in World War 2 were nothing short of amazing!!!!! I likely couldn't afford it if it was for sale,but I can dream !!! I just acquired my first Hamilton Model 21 this week , a US Maritime Commission marked item serial # 2E10600 shown in picture below ,to go with my three model 22 Hamilton deck watches. I am a big fan of this iconic American horological enterprise. And now I'm off to the hospital for dialysis