By Nicholas Manousos
The wheels in your watch deserve a closer look. Are they stamped or cut? What tooth profile is used? Are the pivots burnished or polished? A wheel may seem like a simple part but the manufacturing techniques for a wheel are deceptively complex, which leads to attention being focused on more obvious parts in a movement.
So, if you want to learn what goes into wheel making, where should you go? It just so happens that one of the top independent watchmakers in the world has a series of instructional videos detailing many aspects of wheel making. Let’s take a look at Roger Smith’s YouTube channel for some serious horological knowledge.
First up, Roger explains his process for turning a brass disk into a wheel, by cutting each individual tooth. In watchmaking terminology, a gear is referred to as a wheel. To make things even more confusing, the term wheel may refer to a complete wheel and pinion (a pinion is the toothed hub of a wheel) an individual wheel before it is riveted to a pinion, or an individual wheel which does not need to be riveted to a pinion. In this case, Roger is explaining how to make wheels that will later be riveted to pinions. As you can see in the video, the focus is on quality over quantity. Mass produced wheels are usually stamped rather than cut.
Burnishing Pivots And Fitting A Wheel
Next up, Roger focuses on a work-hardening technique for the pinion’s pivots, and fits the wheel to the pinion. A pinion pivot constantly rotates in a jewel and is among the first parts subject to wear in a movement. Burnishing the pivots helps with their longevity, and reduces friction as the movement runs. Much like his wheel cutting process, Roger explains that his process for burnishing pivots is not meant for mass production. Finally, Roger demonstrates how to rivet a wheel onto a pinion using a Boley staking tool. He first seats the wheel onto the pinion, and then opens the rivet using a small punch and hammer.
Pinion Flank Polishing
Finally, Roger goes into great detail