Wooden V-Pulleys


   I've used plywood pulleys on my grinding machine and found that they have given me no trouble at the low speeds and relatively low power required.  They where turned on my metal lathe so could be made quite accurately, however it did require a lathe and the size was rather restricted.  So, I've tried this idea as a feasibility study and it seems to work fairly well.   The disc was cut from 3/4" plywood and a 1" hole drilled in the centre.  The jig for sawing out the groove was made from two pieces of 3/4" scrap, separated by 3/4" plus a shim so that the disc could be rotated  between them.  A 1" hole was drilled through the jig at a distance from the bottom of slightly more than the radius of the disc, and then the jig was clamped to the saw fence with the hole directly above the saw arbour.  With the blade retracted, the fence is moved till the saw blade is nearly centred on the jig.  The  disc is then inserted into the jig and a 1" hardwood dowel used for an axle.  With the saw running, the blade is raised till it can be heard starting to cut and then the disc is turned by hand, counter to the saws rotation, for a full revolution.  Continue raising the blade by small increments and turning the disc till the grove is ½"  deep.  Retract the blade, remove the axle and flip the disc side for side, and repeat the previous steps to widen the grove.  This also centres the grove in the edge of the disc.  The grove needs to be ¼" wide  so the previous steps will need to be repeated with the fence moved not more than a saw blade width at a time.  Next the retracted blade is tilted to about 18 degrees and the fence adjusted so that not more than 1/8th of an inch is removed at the outside edge (for a ½" V-belt), and the sloping sides of the grove can be sawn in small incremental steps.






    The hub could be done in several ways depending on the pulley's use.  For speed reduction a smaller pulley could be glued to the side and bushings or sealed bearings used to allow the pulleys to free wheel on a stationary shaft.  For torque transmission I've used hardwood hubs drilled and tapped for  3/8" set screws with no problem, or the wooden pulley might be bolted to the side of a smaller metal pulley.

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   Last revised   27 May 09