ei8htohms
8555
I think you're talking about this system (pics)
g
This one was in a Mido (if I recall correctly) and the system was identified in some reference book or another as "Incastar". And it's a terrible idea by the way. You can't regulate it without not only putting it out of beat, but also effectively "peening" or otherwise mutilating the hairspring in ways that require significant additional adjustment to correct.
_john
Not entirely alone.
By: mkvc : February 16th, 2010-00:28
I certainly have a preference for variable-inertia regulators, of which the most typical examples are free-sprung. However, I have a particular soft spot for the old IWC system that combined a variable inertia balance for large adjustment with a regulator...
Explanation....
By: BDLJ : February 16th, 2010-04:49
Hey Graham, In a (very small) nutshell, a free-sprung balance is where the balance spring length is fixed and the adjustment is via the polar moment of inertia of the balance...hmmmm. Bit techy, sorry. From the other direction: On a balance with a regulat...
free sprung vs. regulated
By: tee530 : February 16th, 2010-05:59
Also no expert, but the basics as I understand them: Free-sprung balances vs. regulated balances reflect two different ways of adjusting the rate (fast/slow) of the oscillating timekeeper. Free-sprung have a fixed-length hairspring, and thus the rate is a...
Not always high end
By: nickd : February 16th, 2010-10:33
Elgin produced the Durabalnce free sprung balance, though I don't know if it was ever used in production. FHF produced a free sprung production movement the FHF 72 www.ranfft.de . You see it from time to time on ebay in various watches around the $150 mar...
elgins
By: eterna-fan : February 16th, 2010-11:49
elgin produced tens of thousands of durabalance grade watches. the finishing was spartan, at best, but the movements were excellent time-keepers. i believe the free-sprung caliber 730a was the first wristwatch approved for US railway service. they were no...
More...
By: nickd : February 16th, 2010-13:18
The index pins of a watch with a regulator don't grip the spring perfectly tightly, otherwise you'd have to slacken them to adjust the regulator. Classic theory says the balance is isochronous due, in part, to this gap. As the balance spring oscillates it...