I started messing around with designing a pulley for the motor. Most of you probably know I have a 3d printer by now. So, I wanted to use it to print a pulley which would be infinitely easier than attempting to cobble up something from used parts, and infinitely cheaper than having something machined. The main problem is its made of ABS plastic which is nowhere near as strong as metal. It also can't hold up to engine coolant temperatures (starts to soften around 175F I believe). So, those design constraints will keep things interesting. But, I have come up with what I think is a good and simple design.
The motor has a D shaped shaft end as shown in the picture below. I need to be able to clamp the pulley down so it rotates with the shaft as well as doesn't move front to back on the shaft. My best thought was to embed a small bar of metal in the plastic pulley to give me something solid to clamp to (with the nut that threads on the shaft), and also distributes load so the plastic will not fail. The bar is bolted to the back of the pulley with two #6 screws. The pulley will fit relatively tight on the shaft, but the nut clamps the metal bar to the shaft where the D shape stops, so it carries most of the load.
