Marx windup motors have a lot going for them; they are durable, perform well, plentiful and affordable. However, like any mechanism with an age that is measured in decades, they can develop problems. Over the years I have learned how to deal with the normal Marx issues such as loose wheels, broken mainsprings, malfunctioning governors and slipping ratchets. But, the die-cast mainspring hub will occasionally break, and the only fix I had for that was to find a donor motor with a good mainspring hub. I decided that I wanted to be able to make my own hub in case I couldn’t find a replacement, and while I was at it, I wanted to develop a more durable ratchet, too.
The mainspring hub itself wasn’t an issue except for the square hole for the key. The new hub was machined out of 360 brass, and a 1/8" hole was drilled through it for the keyhole. I made broaches to cut the square keyhole out of the original 1/8" round hole.
Here is a picture of the new brass mainspring hub on the left and an original Marx mainspring hub on the right:
The orginal Marx ratchet uses a plate with pawls stamped into it that engage matching holes in the big gear. Over time, the pawls and the mating edge of theholes get worn out, resulting in a malfunctioning ratchet. It can be repaired, but just for fun I wanted to try my hand a making a more durable ratchet. I soldered a new drum for a ball & ramp style of one-way clutch to an original Marx big gear, then machined a center ramp that pressed onto