Hey guys,

Stocking up on a few items. It was recommended to me that I stash a 'pusher stem for zero action'.

In searching, I've found some 1758 and 1758B, both labeled as 'pusher stem for zero action'.

Why two parts with the same name? And more importantly, which one should I pick up?

(in case it matters, for a 2998-4 and/or a 105.002)

1758:


1758B:


Thanks!

 

Hello.
I would say this is the part you need for the speedmaster cal 321.

 

Thanks @michael e !

 

Just to confuse things further, there is a 320-1758A and a 321-1758A and they differ in length so I would say you need the 321-1758A (caveat - I am not a watchmaker!)

 

I didn't know that Ash. So a 321 1758a smells about right.
Always best wait till someone who knows what the bloody hell they are talking about comes along!

 

Thanks for the help guys.

I think the 1758A is for the chronograph start/stop pusher and the 1758B is for the reset/zero action pusher.

I'm not clear on what the 1758 is though as it is also called the 'pusher stem for zero action'.

These also get sold as 320/321 with no mention of different lengths. Of course, most ebay sellers probably don't really know, but I can't find one that is specifically 321-1758. They all seem to be labeled as 320-1758.

 

give me a second, I can tell you and show you exactly what you need

 

That settles it ( I hope)

 

No, the 1758 parts are all for the reset or "zero action". The one for the start/stop is 1757.

I have never seen the two types you originally posted used in a Cal. 321 Speedmaster. The one you need is the 320-1758a as shown above by michael e.

This is incorrect - the part number for both the Cal. 320 and 321 is 320-1758a.

Cheers, Al

 

Killer! Thanks!

 

remember - merken

 

@mac_omega, what is this merken you speak of?

 

nothing mysterious ... it is "remember" to easily re-find the thread - I have also written the translation for those who don´t speak German

 

I'm sure you're right Al, but Cousins list 'OME3211758A' at 3.5mm and an 'OME3201758A' at 4.25mm. I guess it could be some kind of error by Cousins since the correct length shown by Michael e is nearer the 4.25 of the 320.
Cheers Ash

 

I tend to believe Omega over Cousins, but that's just me. YMMV.

From the Omega 321 parts list (which is likely what michasel e took the above screen shot from):



Cheers, Al

 

incidentally, is there a reason that the zero action pusher is more prone to wear? i've had a few people recommend stashing a couple of these, but I'm not sure why the zero action would be more prone to wear than the chronograph start/stop pusher.

 

I don't think I have ever had to replace one for wear to be frank. If it gets lost or bent maybe, but not for wear. The one for the stop/start is actually a bit of a different animal as it slides onto the operating lever, and I've never had to replace one of those for wear either.

It would not be a part I would consider as an essential spare to be honest, unless you are trying to make sure you have one if it gets lost...it's only a $7 item so not a huge expense if you do get one, but certainly not something I would expect to fail.

Cheers, Al

 

I agree!

 

What parts for the c.321 would you consider sensible to keep as spares please Al?
Thank you
Ash