Building Two Omega f300 Speedsonics

Omega f300 Speedsonic Steel Pair Built from NOS Parts (188.0002)

Omega f300 Speedsonic Steel Pair Built from NOS Parts (188.0002)

Back in February 2015, I collected all the parts to build myself two new-old-stock Omega f300 Speedsonics … and in August 2015, I finally finished building them (it’s not really taken 6 months — much of my time has been taken up with family related things).

The first photo below shows the two cases (188.0002) that I used. The other case (188.0001) in the top right is a Speedsonic Lobster case but I currently lack the lobster bracelet and a mirror dial for this one, so sadly it will remain unused for the time being:

Omega f300 Speedsonic NOS Steel 188.0001 and 188.0002 Cases and Dials

Omega f300 Speedsonic NOS Steel 188.0001 and 188.0002 Cases and Dials

Sharp eyed Speedsonic owners might notice that the wording and font orientation on the black tacky ring (bottom left above) is different from normal Speedsonics. It is a bit of mystery, but there are other NOS Speedsonic cases that have this style of tacky ring although I’ve never seen a finished watch with one….plus, the crystal on this case lacks the normal Omega symbol in the centre of the crystal.

Interestingly, the Baume and Mercier Tronosonic Chronograph (their version of the Speedsonic) does use this black tacky ring and the crystals + tacky ring are interchangeable with the Omega case. In fact, the B&M and Omega cases also share the same pusher assemblies — I know because I’ve had a repair a B&M by using Omega new case parts in the past.

 

 

That took care of the cases (including crystals, tachy rings, pushers, stems and crowns) plus the dials and hands. But the movements were the problem area. Omega calibre 1255, as used in the Speedsonics, is impossible to find. You occasionally see beaten up, corroded ones on eBay selling for silly prices. However, the 1255 is actually an Omega badged ESA 9210 movement and NOS versions of these do sometimes appear.

If it was as easy as popping an ESA 9210 into a Speedsonic case, I wouldn’t be writing this page! Well, actually, it is as easy as that — the Omega dial would fit perfectly, as would the hands, and everything would work as Omega intended. But it wouldn’t be right! 🙂

Here is the reason:

Two ESA 9210 and one Omega 1255 Movements

Two ESA 9210 and one Omega 1255 Movements

In the above photo, the movements on the left and middle are NOS ESA 9210 while the movement on the right is Omega 1255. Besides the day wheels, notice any difference? Yep, the Omega version has red gold plated plates while the ESA plates are nickel coloured — this is the only difference between them and all parts are interchangeable because ESA made all three movements!

But I wouldn’t be happy building 2 NOS Omega Speedsonics and then using these nickel coloured movements in them. I wouldn’t be able to sleep at night even though they’d be working perfectly. At every battery change, I’d feel sick seeing the wrong coloured movement in my watch!

Since 1255 movements are impossible to find, the only solution was to swop all the nickel coloured plates in these ESA NOS movements with NOS Omega parts. Sounds easy but the ESA 9210 / Omega 1255 movement has an awful lot of plates….plus it involved opening up the chrono module.

Omega 1255 Parts

Omega 1255 Parts

I’d had the NOS cases for some time, but I finally got hold of 3 examples of each of the 6 red gold plated Omega movement plates for cal. 1255, as shown above. I bought 3 of each in the hope that one day the lobster case will be used.

And a more detailed photo of each plate:

 

The situation with this last 1255 9001 plate (above) was a little different. I could have chosen to use one of the many Omega f300 Top Plates (cal 1250 and 1260) that I already had since the Speedsonic cal 1255 top plate is identical. However, this plate carries the Omega badge, Omega calibre number and movement serial number, so I opted to pay extra to get hold of these genuine 1255 plates complete with the 1255 badge. Interesting that the serial number starts with an “R” and is not in the normal Omega movement serial number range — I’m assuming “R” means “replacement” or some thing similar.

For those not in the know, my diagram of part of the internals of the chrono module as developed by Dubois-Depraz for ESA is shown below — you can read much more about this movement here. The chrono module rarely goes wrong; most problems arise when it has been opened up by a novice because it can be very difficult to re-assembled if it is done in the wrong order:

ESA 9210 Calendar Platform 2551 Oscillator Side Built Up

ESA 9210 Calendar Platform 2551 Oscillator Side Built Up

The two Omega 1255 movements finished in July 2015: all those nickelled plates from the ESA 9210 movements have been replaced with the Omega version:

Omega 1255 built from NOS parts

Omega 1255 built from NOS parts

Omega 1255 built from NOS parts

Omega 1255 built from NOS parts

August 2015: Finished at last…and pleased with the end results:

 

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