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The hour star-wheelNomos

Tiny Things from the Ore MountainsNOMOS Glashütte: The hour star-wheel

When our workers in NOMOS’ production halls mill, use a lathe, drill, or cut threads, a waste product is metal shavings so small that they can hardly be seen. And the workpieces that are the primary product are hardly larger: 0.4 millimeters in diameter or 0.8 millimeters long – dimensions like those of a computer monitor pixel, an eyelash, or a freckle are normal at NOMOS.

A mechanic, who might elsewhere apply elbow grease, works cautiously here with an instrument called a spiral tweezers. Some sensor devices cannot be seen with the naked eye. Nor touched with a bare hand – the delicate instruments would not survive it. The parts for the fine watches must fulfill the highest quality criteria and meet tolerances often narrower than fourthousandths of a millimeter – and they also aim to be beautiful.

For example, the hour star-wheel of the Xi, NOMOS’ new world time caliber. It is made from a 0.3-millimeter-thick, round steel blank that is first drilled on the CNC machine and then EDM wire-eroded. The high-precision, elegant part is 4.995 millimeters long and has four cogs. Each cog must be at exactly the same distance from the center of the drill hole. That didn’t work on the first try at NOMOS Glashütte: first to be CNC-drilled and then wire-eroded – the hour star-wheel didn’t like moving from one machine to the other. You can’t see the problem, and the tolerances our precision mechanics measured were within bounds. But the watchmakers were unanimous: these hour star-wheels could not be used. Deviations of only a few micrometers had developed and the tips of the four teeth were not absolutely the same distance from the center of the drilling. That was too much for the gears of the world time mechanism. Now the wire-eroding machine does the finishing touches of the drilling – and the hour
star-wheel is right.

This kind of work can’t be taken for granted in the world of watches. To produce independently and to offer constructors the best conditions for implementing their ideas, huge investments were made at NOMOS Glashütte. In this way, even the most pedantic watchmakers get the best parts for their calibers and the customers ultimately get unmistakable movements at moderate prices.