To keep the drive mechanism on my clock simple, it has a drive weight on one side and a counterweight on the other. The two weights are hung on either end of a nylon cord, which passes over the drive pulley. The idea is that the counterweight applies friction on the pulley so that the drive weight turns the pulley. However, the drive pulley on my clock is fairly slippery. I've been wrapping the weight cord three times around the pulley to get enough friction to prevent slipping. This isn't a good arrangement because the cord tends to overwrap itself on the pulley and then jam. This makes winding the clock (lifting the drive weight while taking up the slack with the counterweight) difficult, and also seems to stop the clock occasionally.
So to improve the situation, I mounted the drive pulley back in the lathe and turned a narrow groove that's just shy of the diameter of the cord.
After cutting the groove, I roughed it by gouging with an old small screwdriver that I tapped with a light hammer.
The groove is mostly centered in the pulley, but leaves enough clearance so that the cord clears the cheeks of the pulley (and everything else) on its way out of the clock. The cord sits tightly in the groove, held in place by friction.
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