The gears in a modern automatic winding movement operate such that whichever direction the rotor is spinning in, the rotational effort will be translated into winding of the mainspring. While the arrangement of the gears is simple enough, the real problem is twofold, firstly to do so efficiently, so even small wrist movements will wind the watch, and secondly to do it in such a way that is long lasting. Many early full rotor designs were not the efficient winders we take for granted these days. Also, any time you look in an old watchmakers drawers – you’ll see countless older ETA, AS and even the occasional Eterna or similar design, movements, with their pawl wheels missing and their automatic train holes oval.

The movement we’re looking at in this post is the MST 436/470 Roamer 44 jewel automatic from the early 1960s, in which Roamer, decided to do something much more interesting…
Continue reading →