I always thought it odd that similar movements were not always compatible in regards to parts.

Examples are the bumper movement rotors. Ever movement has a different design which I guess is a development in a more efficient wind until they created the full rotor.

I found it odd that similar parts in 30 mm are also not compatible between movements

Customer needed a 30T2 mainspring barrel, but only one from a non shock movement or previous models would work.

Even odder. Ratchet wheel from say a 30T2rg only worked with two other earlier movements while others worked with all the other movements

Also noticed. Earlier barrels had larger teeth and later smaller and larger number. I assume for longer running times

The odd part. Barrel arbors were the same for all the movements, so space from the upper bridge to the main plate would be the same for all the 30 mm movements

Did some measurements and might be off a point or two due to age of parts

Did 3 measurements. Thickness closest to the edge, diameter with teeth and diameter under the teeth

30T2rg - 2.16, 13.84 and 12.42

30T2PC - 2.16, 13.71 and 12.51

30T2PCSC - 2.17, 13.84 and 12.45

265 - 2.18, 13.68 and 12.53

266 - 2.16, 13.65 and 12.51

267 - 2.16, 13.70 and 12.48

283 - 2.14, 13.70 and 12.48

These are what's left of my 30 mm parts movements, so didn't cover all the movements

Although numbers slightly off. Barrels from 265/6/7 and 283 are compatible

268/9 and 285/6 only work with these 4 movements - same for arbor

Conclusions? Just curious as to what differences if any.

Thanks

DON

 

Hello,

There are slight differences between the calibers of the 30 series. I have been facing the same king of issues. Once, I changed the 3th wheel of a 30T2 with a new one, but designed for a later caliber (I do not remember which exaclty, likely a 283-284). The wheel would fit into the jewels, but would not engage properly with the barrel. So I closely checked and saw the teeth were not shaped the same way.

Same story with a 286. It is pretty obvious that the balances of these caliber are different (not screws, larger and almost flat for a 286). But it is not as easy so see that the train wheel is different as well. I tried to change the 3th wheel with a 283-284: it would fit but every 45-50 secondes, I had some strange perturbations on the timegrapher, because the engagement between wheels was not going properly.

So I checked on the lists of professional sellers of parts. Is is pretty clear that, for certains parts, there are subseries in the 30 caliber series: for instance, the same train wheel would do for 283-284, but not for 286 and not necessarily for a 280. Actually, a caliber number is written on the package of the parts, but they could be good as well for some other calibers, but not for everyone!

I am sure Al will have some insignt concerning this matter.

 

Not sure why this would be considered unusual, but yes just went through a similar discussion here recently:

https://omegaforums.net/threads/283-1305.67256/

People often assume these parts are all the same for some reason, as someone did in that thread and offered a link for an item that was incorrect for the movement in question. What is unusual is thinking that just because the movements are all in the same series, that you can swap all the parts between them. This is certainly not unique to Omega, or the 30 mm movements.
Cheers, Al

 

Since the issue of full rotar invention vs micro rotar has been brought up.

I’ve seen the statement which history seems to support was Rolex patented the rotar and the micro rotar at first was a way to bypass the patent. Once it expired everyone started to use them.

 

Are you sure you answered in the correct thread?

 

Yeah it was mentioned in this one briefly.

 

Indeed! Sorry... My mistake.