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Different mainspring dimensions

jakobvinkas

By jakobvinkas
in Watch Repairs Help & Advice

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jakobvinkas Member

jakobvinkas

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Hello!

I have a ETA 900 movement with a broken mainspring that I am looking to repair. I was looking for a replacement and found this information:

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&&2uswk&ETA_900

With the dimensions: 1.55 x 9.0 x 0.10 x 290

Then when I went to order one on cousinsUK I searched for the movement and found out that they claimed this to be the right replacement:

https://www.cousinsuk.com/category/filter/eta-esa-movement-parts

With the dimensions: 1.55 x 9.0 x 0.105 x 280

Which one should i try to find? will they both the dimensions mentioned do the job? (p.s I do not have the possibility to measure the broken one precise enough) 

Thankful for all answers, regards, Jakob Vinkås

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qhartman Watch Enthusiast

qhartman

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Newbie here, but I'm wondering if the slight increase in thickness compensates for the slightly reduced length? Also, what is the "9.0" in this measurement? I'm guessing is has to do with how much is reverse-coiled?

 

EDIT -  Finally found that it looks like it's the intended barrel diameter. Is that correct?

Edited by qhartman
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jakobvinkas Member

jakobvinkas

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11 minutes ago, qhartman said:

Newbie here, but I'm wondering if the slight increase in thickness compensates for the slightly reduced length? Also, what is the "9.0" in this measurement? I'm guessing is has to do with how much is reverse-coiled?

 

EDIT -  Finally found that it looks like it's the intended barrel diameter. Is that correct?

From what i know, it is the inside diameter of the barrel

 

14 minutes ago, oldhippy said:

1.55 x 9.0 x 0.105 x 280 Will be fine. It has very little differance. 

 

Thank you for the answer, I will order the one from cousinsUK then.

/Jakob

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