I have an engraving spindle that moves up and down to follow the contours of whatever I am engraving. It has a pulley to connect to the motor. It moves fine when it's not connected to the motor, moves up and down very smoothly. When I put on the belt and connect it to the motor it binds a bit and is too hard to move up and down. The spindle is very smooth as well as the race that it rides in, it's the sideways pressure from the belt that causes it to bind.
What I thought would work better is to use a splined gear like on a drill press. The spindle and motor shafts are 5/16" in diameter and I am not having any luck finding anything that small.
Any other ideas to tackle this or a place that has splined gears that small?