I was trying to figure out how to reduce the speed on my tablesaw for an ultra thin kerf blade that has to be kept from overheating. The maker recommends speed of 1000 to 1500 RPM. I have 2.5 inch pulleys on both motor and spindle and the motor is rated at 3450 rpm. I calculated that a 1 inch diameter pulley on the motor would drop me down to about 1500 rpm. The problem is that belts don't like 1 inch diameter pulleys, they vibrate and wear out fast. The smallest that can normally be run is about 1 3/4 inch. I looked at step pulleys as one option because they can easily be swapped up or down to vary speed. I also looked at variable speed pulleys that allow changing the separation of the pulley faces. So far, I don't see any really good options that deliver the desired speeds.
The limits I am working with are that the pulley on the spindle has to be less than 3 inches diameter to avoid hitting the table. The pulley on the motor has to be 2 inches or more diameter to avoid excessive belt vibration. I will eventually come up with a way to do this, but it may take some time searching for odd size pulleys and maybe welding a couple of them together to make my own step pulleys.
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