Sanding a chamfer is a quick way to soften the sharp edge of a workpiece, but it takes some careful sanding to keep the angle and width of the chamfer uniform. To make the task easier, I built a chamfer sanding block that has two runners to guide it along the edge. This way, the angle stays at a consistent 45°. When the desired chamfer width is set, tighten down the screws and start sanding. Stop sanding when both runners make contact with the workpiece. This sander can be set for a 1⁄4"-wide chamfer. But for anything wider than 1⁄8" it’s probably best to turn to a hand-held router. I made the two runners by ripping a piece of plywood with the blade tilted to 45° and then cutting them to length. One of the runners is glued to the block, but the other can be moved in and out to adjust the width of the chamfer.I attach a strip of 1 1⁄2" wide, 180-grit adhesive-backed sandpaper to the flat portion of the block, as shown in the drawing. Installing the adjustable runner helps hold the sandpaper in place.