Training Movement: ETA 7750

Training Movement: ETA 7750

That was fast!

We're in our fourth week, and we're already being introduced to the ETA 7750. The 7750 is one of the most common automatic chronograph movements in production, but it's several orders of magnitude more complex than the 6497 that we've been cutting our teeth on. Here's why:

  1. It's smaller. The 6497 is a pocket watch-sized movement, and is luxuriously large for a beginner. The 7750 is several sizes smaller (though by no means small), which means that the biggest screws on this movement aren't much larger than the smallest screws on our old one.
  2. It's automatic. While our training movement is wound by hand, the 7750 has a mechanism that winds the mainspring through the motion of the watch on its wearer's wrist. For the watchmaker, that means at least a dozen additional components.
  3. It has a date. The date module is one of the most common "complications" (that is, anything besides the basic time-telling functions of a watch), and requires many more parts, but not as many as the next one, which is...
  4. It's a chronograph. This is the big one! A chronograph complication means that it functions as a stop watch. Dozens of components are dedicated to this alone, including many small, fiddly springs and levers.

Traditionally, watchmaking students don't tackle chronographs until their second year, sometimes with only a couple of months left in the program. Our class is taking a different tack. The hope is that with a year more practice, we'll be better-suited for dealing with movements with this kind of complexity in the field.

So, how did it go? We walked into class to find a box with the disassembled movements on our benches, and were told to reassemble them with no technical documents to guide us. By the end of our half-day session, most of us had them ticking!

We haven't dealt with the calendar or chronograph complications yet, but the transition to the smaller movement went just fine. I'm looking forward to seeing what's next!


    Watchmaking student at the Lititz Watch Technicum, formerly a radio and TV newswriter in Chicago.