To help sand large surfaces, I built the sanding block you see in the photo. It accepts a small sanding belt and is great for flattening a workpiece.
As you can see in the drawing, the belt just slips over the block and a tension bar holds it in place. To determine the length of the block, I measured the belt while it was folded and then reduced the length by about 1⁄2". One end of the block is rounded over and the other end has a V-shaped notch cut in it. The notch holds a square tension bar. I also routed finger holds in the sides for a better grip. To use the sanding block, slip it in a belt and slide the tension bar in the notch on the end.
The notch is easy to make at the table saw. After setting the blade to 45°, I made the cuts you see here in the drawing and in the detail.
