Looking for mainspring for Molnia / Molnija 3602, p/n 3379DB

[ManSkirtBrew]

According to Cousins, this is a discontinued item.

1.30 x .155 x 460 x 13.5 DB End

I've checked on Otto Frei and a few other sites to find something close, but I'm not sure exactly what the "DB special end" is.

I did find a NOS replacement on eBay, but it costs more than the whole pocketwatch did, so I wanted to see if I could find new replacements first.

Any other favorite suppliers I should be searching?

[mikepilk]

DB is "double brace", as shown in your pic. There are two prongs which stick out the end, one sits in a slot in the barrel, one in the lid. You could also use DB&H, which is double brace and hole. Just ignore the hole.

Are you sure that's the correct size? 

Ranfft lists the size as 1.85x0.16x400   http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&&2uswk&Molnia_3602

In the GR Mainspring database (I downloaded from Cousins) it shows Molnia 3602 as the size you say, but a comment saying it's incorrect, and has a size similar to the Ranfft.  1.85x0.165x400

 

 

Edited October 7, 2022 by mikepilk

[ManSkirtBrew]

26 minutes ago, mikepilk said:

Are you sure that's the correct size?

I'm not! I was going with the listing Cousins had. I saw that note in the GR database, but thought it was a one-off from someone and figured the Cousins listing would be authoritative.

I'll measure the spring that came out when I get home.

[ManSkirtBrew]

Okay, just measured it. Thickness 0.162mm, height 1.898mm, length 400mm, which agrees with the hand-written note.

Cousins still doesn't list anything of that size, nor does Otto Frei. Unless of course I'm searching wrong, which is highly likely. I also tried a bunch of heights and thicknesses that were close, and didn't come up with anything.

[mikepilk]

4 hours ago, ManSkirtBrew said:

Okay, just measured it. Thickness 0.162mm, height 1.898mm, length 400mm, which agrees with the hand-written note.

Cousins still doesn't list anything of that size, nor does Otto Frei. Unless of course I'm searching wrong, which is highly likely. I also tried a bunch of heights and thicknesses that were close, and didn't come up with anything.

You don't have to be exact on the figures - especially thickness and length.

It's so close to 1.9mm you could probably use this one :

 

[ManSkirtBrew]

On 10/8/2022 at 3:59 AM, mikepilk said:

It's so close to 1.9mm you could probably use this one

Quick update for anyone from the future seeing this post: that's exactly the spring I used, and it works just fine.

[CAPbeats]

Dear ManSkirtBrew,

I’m in the same situation at the moment, so my question is, is your molnija still work now after 3 years? Thank you! 

[ManSkirtBrew]

Sure does!

[CAPbeats]

Thank you!! I was afraid as I have a pocket watch from my grandfather who passed away in 1995 and I already built the the watch into a wristwatch case but still didn’t dare to service it. Now I can start it! Thanks again!