Omega Co-Axial Calibers

In Omega’s own words:

Omega Co-Axial Calibers Summary:

This card showing the Omega Co-Axial Calibers by Family was given out during a Universite of Omega training event for authorized dealers. It is a sort of cheat sheet for sales staff to quickly find Co-Axial equipped watches when serving customers.

CoAxial calibers on this card:

• 8500
• 8501
• 8601
• 8611
• 8602
• 8612
• 8605
• 8615
• 8401
• 8402
• 8403
• 8520
• 8521
• 8421
• 9300
• 9301

Note: The calibers on the Omega training card and listed above are in-house movements with the Co-Axial escapement. They are not the only Omega movements to use the Co-Axial escapement. Since the time this laminated card was produced, more calibers have been released, but it’s a cool relic nonetheless. If you know of an Omega Co-Axial caliber not listed here, please add it to the comments below.

Co-Axial Lift Angles:

The typical watch movement has a lift angle of 52 degrees, but you try to put your Co-Axial watch on the timing machine with that lift angle, you’re going to get an amplitude that is way off.

Most of the 8000 family of in-house Omega movements with the Co-Axial escapement have a lift angle of 38 degrees, but this can vary. For example, some such as the calibers 8806 and 8807 have a lift angle of 36 degrees. Some Co-Axial movements caliber 3888 call for a lift angle of 39 degrees.

Co-Axial Timing Machines:

Despite setting your timing machine to the correct lift angle, you will first need to make sure your machine is compatible with Co-Axial equipped watches.

According to Omega tech sheets, timing a coaxial watch on a timegrapher requires the correct machine. With the older Witschi machines like the red case Watch Expert, Chronoscope M1 (old version), and the Wicometre Professionel models, the amplitude readout will not be measured correctly.

If you are using Witschi timegraphers, you will want to use the newer white case Watch Expert II, Watch Expert III, Chronoscope M1 (updated version). Chronoscope S1, or Chronoscope X1 models for correct measurements. Note that the test mode should be set to <Spe1> on your machine.

Most folks will be using a Weishi or other Chinese made timing machine, rather than the Swiss Witschi timers. If you have not yet purchased a timing machine and you want to be sure to get the newer No. 1900 model  for timing coaxial watches.

Additional Resources:

• Watch a lecture by George Daniels, inventor of the Co-Axial escapement here