Question about Omega 601 Sweep Seconds

[dman2112]

Hello all,

I am restoring an old Omega Geneve with Cal 601 and while I was disassembling the movement I neglected to note the position of the 'pressure spring for sweep seconds pinion' against the leaves of the actual pinion itself.

 

Should the spring provide pressure to the pinion against the pinion cock (underneath the leaves) or shall it be positioned providing pressure against the top of the leaves (between the cock and the leaves) so to push the pinion towards the watch dial?

 

Any clarification would be appreciated.  Thank You

 

 

[frenchie]

Welcome to the forum!!!!

The spring goes under the pinion, pushing it towards the cock (away from the movement)

[dman2112]

Thank you!  Cool thats how I installed it.  Amazing what happens when you stare at something a little while and apply logic. :-)  Thanks for the info.  Much appreciated.

[Tiktok]

It's also quite important to get the correct tension on it, too much and the amplitude will drop, not enough and the second hand will have too much play in it.

[dman2112]

Roger that. I didn't adjust it, but I am achieving 271deg amplitude in most positions and 278 with the sweep pallet cock removed. Does that sound correct or shall I try to equalize the springs pressure to squeeze out a few for degrees. FYI the mainspring is new

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[Tiktok]

Once the hands and dial are fit you can do a visual check. If you hold the watch in the 12 up position and watch the second hand come down from 12 towards the 6 position. As it pass's the 6 and starts to go up back towards 12 it should be a constant sweep and not judder back as it fights gravity, you can also give it a slight tap to make sure the second hand still doesn't drop back a second or two. Repeat this as it pass's 12 to make sure it doesn't jump forward slightly.

presuming you have already checked for up and down end shake, which would be obviously not enough tension then the amplitude seems good, it's not even dropping in the hanging positions, although this might change when you get the hands and dial on its perfectly normal.

For future reference a good test for the tension is to spin the train before you put the pallets in by slightly winding the mainspring and then release the tension on the pinion friction Spring, if the 4th wheel turns a couple of times then normally you are somewhere near the correct friction. If the wheels spin loads of times the friction is too much, and if the wheels don't spin anymore you haven't enough friction on the Spring.

[dman2112]

Thanks. Good technique on the check. Much appreciated. I neglected to mention the numbers I mentioned above are with dial and hands on. I'm going to recheck with the gravity method to confirm.

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