It was time to change the belt on my sander. While I was at it, I decided to pimp it up. Here's my minimalist approach to attaching a solid, square fence to a portable belt sander.
Step 1: Portable Belt Sander
I bought this sander a few years ago from Harbor Freight. There was a dizzying array of models to choose from. This one had an adjustable handle. When laid flat, the sander can be laid on its back, and it's quite stable. I figured I would convert it into a bench sander, and this feature would save me some work. Even if your belt sander does not stand on its own, this instructable may still help you to attach the all-important fence. See, the fence must be square to the belt if you want to create and/or retain nice, square edges.
Step 2: First Attempt
This was my first attempt at attaching a fence. It worked good enough. I used it for three years, and it got the job done. But there were a couple of annoyances with it. As I used it, it "broke in" and the fence tilted. Once it finally settled in, I resanded the face of the fence straight again. That's the most important bit. But the top surface of the fence was no longer in a parallel plane with the belt. This plays tricks on your eyes when you're trying to sand stuff. So I decided to do it again, and to do it better.
Step 3: Basic Problem
The essence of this project is to get the fence to be secure and square. So here's what we're looking at. The belt rides over a flat metal plate. I want the fence to be as close the the back edge of that plate as possible, and still be secure. There's not much there to support the fence. At first glance, this looks like mission impossible. But with the help of physics and some shimwork, it is not as daunting as it may at first seem. All we need to do is support the fence at the four corners, leveling it with shims.
Step 4: Making the Shims
The fence is going to be a 1.5" tall square block of wood. I want it to be exactly square and in parallel with the surface of the belt. In my estimation, the easiest way to do that is to make some shims. Afterall, a belt sander is a great tool for fine-tuning shims in no time flat! See the pics for the play-by-play.
Step 5: Attaching the Fence
Now to attach the fence, it doesn't take much strength at all. I use just two thin strips of wood to screw the block to the housing. The way the block is attached, it will only push back and down when ur using it. Since the shims keep the block square when you push down on it, I just need two little strips attached in such a way to prevent the block from going back!
Step 6: "Spindle Sander"
Before I put it back together, I decided to cut away part of the front housing. This exposed the front roller, allowing some sanding ability on concave surfaces.
Step 7: Done!
Doing this "correctly" turned out to be much easier than I would have thought. This fence is very stable, very square, and I foresee it being in use for many years to come.