Built myself an edge sander/ bump sander/ call it whatever you want sander about three years ago. Thought I would share. It takes a 6×108” belt. I copied the tracking/tension mechanics off of an older Crouch sander I liked. Very simple, runs good, should have built it sooner. Sometimes you build a jig or tool (or buy one) just because you can, and then find its not really used very much. I have never regretted this build, I use it every time I go in the shop. I did upgrade the motor, what I started with would work if you were easy, but who wants to work that way.