Need to find the dimensions for the 590-591 mainspring . Bought a mainspring from cousinsuk and not sure it's the right sizes . Have search but can't find any info.

 

I don't have it in any of my references as it's an unusual calibre but, Cousins sell the Omega mainspring - 5901208. Safest to buy that one as it will be correct and is only about £12.50.

Cheers, Chris

 

Given Omega's current mainspring prices, this is a bargain!

 

Having trouble with the amplitude of the movement. Bought mainspring from cousinsuk . I was thinking it's not the correct size. So i wanted to know if someone had the dimension so i can compare them with the original mainspring. cousinsuk has been wrong before.

 

A cracking deal - and you don't get many of those!

If the mainspring was in Omega packaging, then it is correct. The "590" is the calibre and "1208" is mainspring so, the part number is 590-1208 (old packaging) and 72205901208 (new packaging). This also applies to all the other calibres, so the 550 series would be 5501208, and so on.

I just looked at the parts list for the 590 and it looks a bit like a cross between a 500 and a 550 series. I've never seen one of these and virtually every part is 590 specific. Although the diameter is similar to the 550s, the thickness appears to be greater than the equivalent 552. If you have a generic mainspring, then I would say (if the barrel is 10mm diameter), 0.100-0.110 mm thick at whatever height suits the barrel and a length of about 400-360 mm. If you're struggling for amplitude with a spring like that, then it's probably a different issue - I assume it's more than just 35% struggling?

Cheers, Chris

 

Not me working on this. Thank god. I am trying to help a friend that is struggling with this 591 from hell. He has had lots of trouble like incabloc spring and the post for the rotor. He says if he winds the MS full he gets 240 amp . But just for a couple of minutes. Then i drops to 160 . I am sending him some breaking grease to try out. My thinking is that the MS is slipping.

 

Unlikely that sort of drop is because the mainspring is slipping...in most cases low amplitude is not related to mainspring problems, but wear in the train. He needs to check all pivots, all jewels, make sure end shakes are good, He should also also check for wear in the barrel drum and cover, and where the barrel arbor goes into the main plate and barrel bridge. These are both places where wear can allow the barrel to tip inside the movement, cause drag, and kill the amplitude.

 

Think he has checked the barrel bridge and mainplate. Everything is okay. He has done lots of watchmaking so i guess he knows where to look. One thing i was thinking is if the barrel drum and cover as you said. That could very well be the problem. I wonder if he has the old MS left. It would be easy to measure how high it is.

 

The 590 mainspring is Height - 1.25 x Stength - 0.105 x Length 340 (Barrel diameter - 10)