An advertisement from the period for the Omega Speedmaster list a 42mm case size for the 105.012 & a 40mm case size for the 105.003. Have there been any other variations in case size during the production of the Speedmaster/Speedmaster Professional?
There was a slight size difference between 2998/105.002 and 105.003 too wasn't there? Or it might have been a variance in proportions of dial/bezel
The bezels are a different size, but don't think that there was a difference in the case size, not sure though
Yea I really don't know for certain either, bezel is definitely different as is dial, will have to wait for Moonwatch Only to arrive from D
I know that these vintage Ad´s with drawings are no good for Reference, but i find it very interesting that the 105.003 has a polished tension ring and not a black one
You will not manage to screw a 2915 caseback in a later case and vice versa. It seems like it is due to the thread beeing different. Further differences in cases between the different straight lugs are of course the diameter of this little depression for the pushers as they got slightly bigger over the time.
Oh dear. So now when i next get home (April) its going to be out the the vernier to check all the little pusher depressions in my straight lug cases to check they really are with the right caseback. My ADD is kicking in. I know that a 105.012 back goes on a straight lug case because i just bought one, and fitted a correct 003 back i had lying around. Except i didn't check the depression size.......