Hi all,

I might be nitpicking, but it just occurred to me that one of the screws in my cal 8900 is not blackened, but rather a 'plain' steel one. Apart from this one, all other screws in the movement seem to be blackened.

It is the one underneath the medallion, next to the blackened one on the right.

Why would Omega do this? Or is it just my movement?

 

Difficult to be certain from your picture, but this happens frequently on Eta automatic wind movements. I m unable to say this applies to the movement in your watch, but many Eta movements with auto wind, have the auto wind system removeable from the base movement as a unit. These auto wind units are usually held on with screws with blued heads, while the rest of the screws will be polished steel. Remove the screws and the auto wind systems comes off as an integral unit.

 

Looks standard, FWIW. Compare this image from Omega, you can see the screw in question peeking above the hub.

 

My AT with the same movement. You can see more than one non-blackened screw.

 

My Planet Ocean with the 8500 movement is the same. Here’s a lousy photo that shows it.....

 

Looks normal to me, here’s my GM

 

My Globey’s the same way.

 

Ok, so no worries. Any ideas on why Omega does not bother to give all screws the same treatment? It looks rather sloppy to me this way. A bit inconsistent. The rest of the movement is quite nicely finished.

 

There is a reason:

The three blackened screws are what hold the auto module in place.

 

Next time your car is at the mechanic’s shop and it is up on the hoist, if the mechanic invites you to have a look at the side only the road sees, prepare yourself for a shock!

 

There are 6 screws for the automatic winding module. The three black screws are what holds that module to the rest of the movement. The three silver screws are coloured this way so that the watchmakers know that those are the three screws that hold the module itself together. So if you are disassembling the movement, you remove the three black screws to remove the module, then the three silver screws to disassemble the upper and lower plates of the module to remove the wheels inside it.

It's designed this way on purpose.

Cheers, Al

 

Thanks Al! Your insights are much appreciated.

 

I love this guy!

 

Well book a room and hope that Al feels the same way.

Kidding of course, we all love Al and the wealth of knowledge that he freely gives to the forum.