Swiss PW MAINSPRING Needed for PL Longines Pocketwatch

[Brad Maisto]

I need a mainspring for a 43-44mm diameter Longines PL pocketwatch that has the caliber number, either 19.25 or 19.75. The "2 or 7" can be interpreted either way due the script it is engraved in. I have removed the broken mainspring, and it measures 0.007 thick and width of 0.088 inches. These numbers convert to roughly 0.17mm thick by 2.23mm in width. I believe the spring to be about 21 inch in length with a T-end. The length may not be so critical as this watch has a Geneva stop-works on the bottom cover of the mainspring barrel. I can post pictures if anyone is interested, but I would appreciate assistance in this matter. Thanks in Advance,
Brad Maisto, Indiana Chapter 18 President
P.S. I would prefer a white alloy MS, but will settle for blued steel if it is my only option.

 

[Brad Maisto]

Couple of pictures of the watch needing a mainspring:

 

[Journeyman]

Hi

Given the width of your spring at 0.88" (approx 2.2mm) your movement is 19.75

The Generale Ressorts SA Bienne Suisse No for your spring is 6304-T H. 2.2mm Th. 0.22mm L. 500mm Barrel Dia. 17mm


Peter

 

[NC Plumber]

I looked through a lot of my springs, and found one that has a tongue end, but none with a T.

 

[Brad Maisto]

Peter and NC Plumber,
Thanks for the assistance and I think I may have come up with a solution. I received another e-mail saying that this caliber 19.75 Longines requires a 14 dennison mainspring and 20.5 inch long. I found a Waltham #2208 that has the t-end and is the right dennison width (close to 2.25 to 2.30mm), but is the old blued-steel type. I'll measure the diameter of the barrel and report back as to whether or not this spring will really work.
Thanks Again for the Input and Comments, Brad Maisto

 

[Brad Maisto]

Repair complete and the Private Label Longines caliber 19.75 movement is running fine and keeping "RailRoad" time. The diameter of the mainspring barrel measured just at 16mm and the Waltham #2208 fit perfect, like it was made for this caliber Longines movement requiring the t-end mainspring. And putting the Geneva stopworks back together also went smoothly.
Thanks for all of the Help,
Brad Maisto
P.S. I may have exagerrated just a bit the the time keeping precision, but it did keep up with my Rolex wristwatch !

 

[Kevin W.]

I just found this thread. I have the exact watch movement.
Nice to see others out there.