Coaxial escapement does not fulfill their promise

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It's quite funny that I would write an entry on horology - aka high end mechanical watches - when I don't own any, at least for now. I did own a modded Seiko SKX007 a couple of years back, only sold it because I never wear it due to its weight.

Despite my non-ownership, I just find mechanical watches fascinating as tiny mechanical marvels, and enjoy reading about them.

This article came from my frenzied (and really pointless) research into coaxial escapement a few years back, and I decided that it's better to record my findings so there's something to show for my efforts.

In horology, the coaxial watch escapement largely eliminates sliding friction, which offers the following theoretical advantages:

  1. No lubrication required
  2. Which leads to longer service intervals

However, MORE lubrication is required in practice, as testified by Roger Smith, renowned watchmaker who make use of co-axial escapement:

One interesting point about the co-axial escapement is that the impulse surfaces are oiled (hence "[lubricating the escapement is] theoretically no longer necessary"). However, it's not to reduce friction. Instead, the oil is there to minimize impact oxidation. By email, Roger Smith told HODINKEE, "We apply lubrication to our single wheel teeth, as did George [Daniels].

A Omega Trained Watchmaker Dispels Co-Axial Myths

All quotes by Archer, an Omega Qualified Watchmaker

It is difficult to tell if you have correctly lubricated the movement:

One thing with a co-axial is that even if you don't oil the escapement properly (which is the biggest difference in servicing them) the watch will run fine on a timing machine, and this often gives watchmakers who don't have the training the false impression that the job has been done correctly. So for example if you don't lubricate a Swiss lever escapement, you will see it quickly on the timing machine, but not so with the co-axial. Everything will look fine, but the escapement will be chewing itself up.

And when asked about service interval improvements:

I don't know what their goal was in terms of a number of years of extended service interval they were seeking. All we were told was that the goal was a longer service interval.

But does changing the air filter in your car to a better type extend the life of your tires?

There are far more work involved in lubricating the movement:

The lubrication on the co-axial wheel teeth acts as a cushion against impact. The lubrication on the intermediate escape wheel teeth (where required) though is designed to reduce sliding friction.

In a Swiss lever escapement I place oil on one spot (exit stone) and typically have to apply 3 small drops of oil to fully lubricate the escapement.

By comparison in a 2 level co-axial escapement I have to individually oil all 20 teeth on the intermediate escape wheel, all 8 teeth on the lower portion of the co-axial wheel, and 2 teeth on the upper level of the co-axial wheel. That's is 30 individual oiling points.

In a 3 level co-axial escapement the intermediate escape wheel teeth are not oiled, but the same 10 teeth on the co-axial wheel are oiled.

There is far more oiling involved in a co-axial escapement than a Swiss lever...

Not worth it

At the end of the day, co-axial movement are

  1. More delicate
  2. Complicated to service
  3. Difficult to service correctly
  4. Requires expensive and exclusive parts from Omega
  5. Requires Omega trained watchmaker

All that and it doesn't even improve service interval, due to the rest of the watch still having their own (shorter) service intervals.

And if the watchmaker open your watch up anyways, there's no extra cost to put 3 drop of oil on a Swiss Lever escapement while they're at it.