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Robert wrote:
A question was asked on the other list by Red about mechanical chronometers.
I can stop by and read the list but am unwilling to join so I can not post
to that list. I have an interest in chronometers and collect them so I
wanted to speak to that question while I have the chance.

You asked about what makes a ships chronometer a chronometer. A chronometer
is not always a great time keeper but it is instead a constant time keeper.
The rate or error is always the same so that you can correct the reading of
the dial to get GMT.

They differ in construction from a watch or clock. The common configuration,
and that is of both the Hamilton and the MMX is to have a chain drive with a
set of steps in it so that the power from the main spring is transferred
evenly as the spring winds down. The steps change the leverage of the drum
as the chain winds from one drum to the other. The steps are arranged in two
pyramids with the small end of one at the large end of the other. You also
have a maintaining spring in addition to the main spring. It keeps the works
running while you are winding it. The balance wheel is poised in the face up
position and is biased to temperature compensation because the gimbals keep
it in a face up position. A railroad watch on the other hand is poised in
more positions but is not as well compensated for temperature. It was
intended to stay in the conductors pocket and stay at an even temperature.
You can poise a balance wheel for one or the other but not both. You can not
regulate !
 a chronometer in the way you can a watch or clock. The balance weights need
to be adjusted and that affects poise so it is very difficult to do with out
the service tools.

I have a MMX and the gold plated movement is beautiful to see but my
Hamilton is a much better chronometer and has a lot of features that the MMX
does not have. I have the original service book for the Hamilton and it
describes the design and unique features of that design in great detail. I
can copy parts of it if you need some information. My documentation on the
MMX is not in English needless to say and I have no idea what it says.
Robert Gainer

Robert, I wish you would join that other list too.
I just sent a post into it (a few hours ago) dealing with mechanical
chrono/watches.
Funny you mention Hamilton Watches in your post as I did in my reply on that
list.
I have a Hamilton Model 23 Type 5747-1 Navigational Watch. That watch has
temperature compensation built into it. That is what I was
describing/telling a poster over there. No other watch comes close.

   

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