Micromechanics, Part I

By request, today I will go into more depth on my micromechanics training. To review, I attended the Lititz Watch Technicum. It is a WOSTEP Partner school in Lititz, PA fully funded by Rolex. The first major segment of the training covers micromechanical skills needed for watch repair. Before we ever started working on actual watches we worked with saws & files & burnishers & lathes, etc for about 9 months.

I remember clearly our first task. It sounds so easy now, and I could probably complete it in about 15 minutes, but it took me (and my classmates) several days. The goal of this task was to hone our measuring, sawing, & filing skills.

CylindersWe were given a section of 6mm brass rod and we were to prepare four sections as follows:

  1. A section 40mm long +/-.40mm
  2. A section 30mm long +/- .30mm
  3. A section 20mm long +/- .20mm
  4. A section 10mm long +/- .10mm

Both ends of all of these pieces had to be perfectly square with nicely formed 45 degee bevels. We could cut them with a jewelers saw and then file the ends exactly to length. Their could be no marks on the cylindrical portion of the rod from any tool, or the vise.

DiceOur next task was to make a brass die 10.0mm cube from 12mm square brass stock. Of course all the sides were to be square, flat, and with straight even file marks. The “dots” were to be scribed as we were instructed, marked with a center punch and countersunk to remove any burrs. All of the dimensions were to be within 0.10mm, measured from any point on one side, to the corresponding point exactly opposite it. To put these dimensions in perspective a piece of notebook paper is about 0.10mm thick. We are talking less than 1/100th of an inch. (Honestly it seems huge now!).

SteelSquareOur next project introduced us to steel. Steel is much harder than brass, but an extremely common material in watches. We formed a square from a cylinder (the hard way, without using a lathe and a file rest). Once again, everything had to be square and the dimensions were now +/- 0.05 millimeters. This would prove a useful skill when making winding stems.

Our next project was our first tool. It introduced the drill press. It was a Bow Tie shaped Base with 10 Holes to hold stumps and pushers for our <a href=”https://ticktalk.wordpress.com/2008/01/22/horia-jeweling-tool/”Horia tool, which we would make later. All the outer dimensions were to be within 0.10mm of the specifications as were the diameter of the drilled holes. I don’t have a picture of it, but I still use it. It is in my bench today holding all of my custom Horia tool stumps and pushers.

SpheroidsThis brings us to our first exam and the end of today’s post. A spheroid. From a square block of brass we were to form a “spheroid”. The point of this exercise to learn to file curved parts. There were no specified dimensions, we were given a technique and symmetry was the goal.

Part II
Part III

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