I don't have a 3D printer---gave mine to my daughter---but this article appears to be very intriguing. Considering the amount of time I've spent sanding+filling (infinite do-loop), if I did have a printer and knew how to use it, it would now be printing the sander parts, and I'd be looking for a small used motor. There are also videos on making a mini drill press, a mini table saw, and even a tiny lathe from heated and flattened PVC pipe. (I think good tough hardwood or sheet metal would work for many of the parts.)