Monday, September 5, 2016

The Mystery of the Date Wheel Dots on Swiss Army Titanium Airboss Chronograph Limited Edition

The titanium Swiss Army limited edition Airboss chronograph is no stranger to this blog. It has appeared several times in different articles including "A Rare Pair of Titanium Airboss Watches..." and "Strap Swap for Titanium Airboss...". This is one of my favorite watches that I personally own.

Swiss Army Airboss Titanium Chronograph. Photo: Stephen McGee
Recently, a watch collecting pal of mine was lucky enough to buy one for himself, and we were comparing our specimens. As you can see, the satin titanium picks up the local colors of everything around it. It can be a bit of a chameleon depending on the light.

Swiss Army 241599. Photo: Stephen McGee
Everything was identical, and we found ourselves basking in the glory of this killer watch. Stephen takes excellent natural light photos of watches and I begged him to let me include a few.

The date wheel dot can be seen at extreme angle and directly above.
Offhand, I told him that I thought that my watch might have a manufacturer's defect because it has dots visible on 3 different spots of the date wheel appearing between 6 and 7, between 16 and 17 and between 26 and 27. I had never seen this on other watches so it caught my eye.

The locations of the dots on the date wheel at 6-7, 16-17 and 26-27. These normally don't show.
He confirmed that his watch had the same dots in the same locations so I immediately suspected that it was not an individual defect, but something built into the date wheel. If one imagines the date wheel as a pie chart, then the dots represent a 360 degree circle split into 120 degree slices. What could be the purpose of these dots?

I found an image of a Valjoux 7750 movement's date wheel, and the dots were visible so this does not seem to be out of the ordinary. However, seeing them from the front of the dial is a little unusual.

3 dots appear on some Valjoux 7750 chrono movements. Photo:
I suspect that either the designers of the watch did not mind these dots showing or they did not take them into account when sizing the date window. It could be a milling miscalculation resulting in a slightly wide date window. Some dials have a frame added to the edge of the date window which could hide the dots, and many date wheels do not have the dots at all.

In the end, I'll just call it a quirk. It does not add to the aesthetics, and it could be seen as an oversight, but I just consider it a freckle and it does not bother me too much. Plus, the dot will only appear 33% of the time. It will be fun to see it on occasion.

Yep... Another photo of the Airboss Titanium by Stephen McGee.

Watch Guy Blog
Anyway, this minor personal discovery proves that watches reveal secrets as you spend more time with them. It also proves that I do not fully understand the engineering that goes into the magic gears and levers in these watches. That will take me many years to begin to grasp how everything works together.

Thank goodness for blogs like written by a professional watch smith, Christian Dannemann. The topics covered there will help anyone looking to understand how these mechanical wonders work, how they can break and how to fix them. He let me know that the dots are most likely used to align the print with the teeth on the date ring. Thank you to Christian and Stephen for letting me use their photos.

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