The belt sander is a machine that rotates a sandpaper at high speeds to remove material from a workpiece. The workpiece is held by the user, either in hand or on the work surface, and material is removed by pushing the workpiece against the sanding belt in short passes. This machine is best used for removing small amounts of material from convex sections of a part. Keep in mind that while the belt is flat, pieces pushed against the belt sander will be sanded to a gentle curve rather than a flat surface, due to deformation of the belt. You may use this machine for your hammer handle, but you do not need to. After you turn the sander off, make sure you stay with it until the belt comes to a complete stop.