Unitas 431 445 Mainspring

[ramos3120]

I am trying to source a mainspring for a Unitas 431 445.  It seems to be discontinued 

[Nucejoe]

Measure the dimentions of old one, general resorts  GR still makes most sizes.

rgds

[mikepilk]

3 hours ago, ramos3120 said:

I am trying to source a mainspring for a Unitas 431 445.  It seems to be discontinued 

If you search on Cousin's "Download Documents" for "GR mainsprings" you can down load the whole GR database.

Here's the part you need for Unitas (pages 182-187)

Look for the closest spring they have. Try to match the thickness first (0.21), then width (1.90). The length isn't as important. A shorter spring will just give less running time.

[Razz]

Emmywatch also seems to be a decent source. It lists 3 different mainspring dimensions with 2 different GR numbers for the Unitas 431. Also a parts list and a few other pieces of data. So it looks like you might need to measure the barrel as well.

unitas 431

 

 

Edited November 18, 2023 by Razz

[tadelstein1948]

The Unitas 6431 6445 and Cortebert 726/736 appear akin to the 431. 

[mikepilk]

According to the Jules Borel database, it's common to a lot of movements