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Automatic mainspring barrel 'Brake Spring' for AS 1902


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Hi,

I have a Rotary Monza I am fixing up. I disassembled the barrel and removed and cleaned the mainspring. I secured a copy of the parts list and it shows that as well as the mainspring, there is also a Brake Spring (part 775 on the picture). What is it, and do I really need it? Certainly Cousins does not sell it. I googled AS 1902 brake spring and ONE result came up of a Russian watch forum discussing this item. Apparently it is thicker than a normal spring and it seems to have some sort of bent over feature on it. Can I just make one using the old mainspring? If so, how long should it be? Is it really necessary?

https://translate.google.com/translate?hl=en&sl=ru&u=http://forum.watch.ru/showthread.php%3Fp%3D5196915&prev=search

ROTARY Monza AS 1902.pdf

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3 hours ago, Plusfoursmax said:

Hi,

I have a Rotary Monza I am fixing up. I disassembled the barrel and removed and cleaned the mainspring. I secured a copy of the parts list and it shows that as well as the mainspring, there is also a Brake Spring (part 775 on the picture). What is it, and do I really need it? Certainly Cousins does not sell it. I googled AS 1902 brake spring and ONE result came up of a Russian watch forum discussing this item. Apparently it is thicker than a normal spring and it seems to have some sort of bent over feature on it. Can I just make one using the old mainspring? If so, how long should it be? Is it really necessary?

https://translate.google.com/translate?hl=en&sl=ru&u=http://forum.watch.ru/showthread.php%3Fp%3D5196915&prev=search

ROTARY Monza AS 1902.pdf 1.95 MB · 4 downloads

Modern automatic springs are just a single part, they don't have a separate 'brake'.

The part you need is GR39981X

https://www.cousinsuk.com/product/145mm-height?code=GR39981X

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