Right-Angle Sanding Block Keeps Edges Square

If you're not careful, you can put a subtle chamfer on the edge of a workpiece by sanding it freehand. To keep your corners crisp, build the right-angle sanding block shown above. By keeping the plywood top flat on the face of the workpiece, your sanding will always yield a clean, straight edge that's perpendicular to the face of the workpiece.
—Ted Kusmak, Alexandria, Minn.