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drive belt Pinch Pulley's for watchmakers lathe

One of the first projects I took on after getting my antique WW lathe was to improve the traction of the belt drive system. These little lathes are notorious for having the drive belt slip under only moderate loads. This helps in protecting the lightweight head stock and spindle but they are capable of doing a lot more if protected and outfitted properly to decrease load.

For me, this issue was a matter of traction not of tension. Increased belt tension would unduly wear on the hardened cone bearings of the headstock. My solution was to increase how much of the circumference of the headstock pulley was to be in contact with the belt. I decide to make a device to pull the belt around more of the headstock pulley. These pinch rollers would sit between the headstock and the counter shaft setup. Once installed, I was amazed at how much more robust the traction was. I can now take much more reasonable cuts without sacrificing the safety of emergency belt slippage from a jam and there I am able to keep the belt less tensioned rather than more.

Lathe pinch pulley frame
All parts of the pinch pulley rig were fabricated from scratch in steel, brass (and aluminum for the pulley wheels themselves). High speed ball bearings from large RC racers were pressed into the pulleys. They run very quietly.

lathe pinch pulley carriage installed
Just for fun, I make the top of the support column decorative with a tiny brass finial on top.

lathe pinch pulley showing adjustable clevis

Lathe pinch pulley increases traction

Lathe pinch pulley


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