poljot 3133 mainspring

[FranRod]

Hi, I am going to try my hand at a chronograph for the first time. I have sourced an old Poljot 3133, but before enrolling in the course I want to gather all the missing parts and I am having a hard time sourcing a mainspring for this movement... Can anyone give me a specification/provider for this? what I have found in the interwebs is not available at any of my usual part sources...

 

Thanks in advance!

Edited August 1, 2023 by FranRod
typos

[RichardHarris123]

Has it already got a mainspring?  If so you could measure that, we can give you further advice. 

[Jon]

2 hours ago, FranRod said:

Hi, I am going to try my hand at a chronograph for the first time. I have sourced an old Poljot 3133, but before enrolling in the course I want to gather all the missing parts and I am having a hard time sourcing a mainspring for this movement... Can anyone give me a specification/provider for this? what I have found in the interwebs is not available at any of my usual part sources...

 

Thanks in advance!

Have a look at this

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&2&2uswk&Poljot_3133

It is a useful database for many movements, including hand sizes, mainspring sizes, balance staff, etc.

If you go on Cousins website https://www.cousinsuk.com/category/filter/eta-parts-search

It will say the spring should be 0.14 thick. This movement is in effect the same as a Valjoux 7733. I fitted a 0.14 spring into a Valjoux 7733 this week and got 350 degrees in amplitude and bad knocking, so that spring was way too strong, by a strength (0.1 mm) The spring needed is 0.13 thick as quoted by Ranfft

Edited August 1, 2023 by Jon

[FranRod]

Thasnk Richard and Jon for your replies,

I had already done the Ranfft/ Cousins thing, but I cannot find anything close to 1.60 x 12.5 x 0.13 x 430mm (with a DB end, which these mainsprings have). I was ideally looking for a GR reference.

I don't know if there is a current Mainspring that would fit, or I should look for NOS /second hand parts.