Having learned my lesson previously, if I can’t source something through more traditional means, I will sometimes order a needed part multiple times on eBay, from a different source each time, because one can’t be sure. At the same time, I’ve found parts on eBay that I couldn’t find anywhere else.

And how would one know?

So, I ordered part 321-1730 (not to be confused with the two hole version for 320 movements) from four different sellers on eBay. One in the USA, one in Canada, one in the U.K., and one from South America. One seller had them in sealed Omega packets.

This is the part that broke in my Sotheby’s 105.002-62, which prevented the chrono from resetting.


A photo of the group, before I opened one of the sealed packets.

And here they are arrayed, always in the same order.


You can see two things clearly:
A - Some of them are worn and some new - look at the lobes at the thin ends.
B - Omega’s parts manufacturer simplified the piece in later years - look at the ‘arm pit’ curves; the older ones have deeper curves

(There are other subtle differences as well.)

The sealed ones came from the U.K. $90 for two - shout out to fullywound on eBay for being best and cheapest
1 came from the USA $75 - seller said it was new in ad but photo wasn’t clear
2 came from South America $40 - seller said it was new with defect, but I don’t see it
3 came from Canada, $65. - seller said it was new, had good photo of item

So, there you have it. And no, I didn’t think this was a waste of money. These are expensive watches and I try not to scrimp on service or finding the right parts. I was curious to see what I’d catch.

And, I’ll probably do it again sometime.

NB - Of course, if one has the option, buying factory sealed parts is always preferred.

 

Part No.3 looks every bit as good as the sealed one. the others all have identifiable issues that may not make them less functional, but certainly make them look worn.

 

To my eyes, the lobe on 3 isn’t as full as it is on the sealed one or 2

 

Maybe the sealed ones reflect a slight design tweak by Omega to add strength at the spot where the part is most vulnerable to breaking? That is my take on it, vs they went for less expensive machining.

That is a great comparison though, and shows it is dicey to buy used parts if the part in question is one that sees a bit of wear in use.

 

funny that this is the part that broke on you. I've had two - one bent, the other broke, both resulting in non-functional chrono. It was easy enough to find this part in particular, but it seems like such an odd piece to break...

 

My watchmaker said the same thing.

Here’s where the part goes in a 321 movement:


Actually, I just realized that this is a photo of that very 1730 before it broke.

 

Makes me wonder if a part that is pushing on it periodically may be moving more than it should due to wear, resulting in this part breaking. (i.e., there may be another part that should be replaced to keep this from happening again any time soon)

 

It's not surprising at all that is fatigues and breaks IMO. Both ends of this spring are moving every time the chronograph starts or stops. The "lower" half that presses on the coupling yoke moves only a little, but the "upper" part that puts pressure on the hook that actuates the column wheel moves a fair distance with each press of the start/stop pusher.

I don't replace a lot of them, but I do replace them from time to time. BTW still available from Omega new, for a lot less than the secondary market is charging generally.

Cheers, Al

 

#3 reminds me of the island of new giunea, sort of little kid dinosaur shaped.

thanks for the effort to document the variation in this part.

 

BTW just to illustrate how much the upper half of this spring moves during the switching of the column wheel, here's a video showing just that I made a while back:

If you look at the amount of flex in the spring due to the column wheel operating hook movement, you can see clearly why this part breaks where it does eventually. No mysteries here.

Cheers, Al

 

Fully agree with you about buying part in sealed factory package.

When I had to replace my Adjusting Spring for Regulator on a 565 , I need to order 4 of them before finding the good one.



1st wasn't flat behind, so impossible to fix.
2nd distance between hole were not as the original
3rd Genuine part but with a different shape despite the fact it have the same number.
4th the good one.

So even in genuine parts, there is some change.
And I keep in mind one remark from Archer that there is a difference between NOS parts and original parts.