Banjos are held together with a circular steel band. The band sticks up slightly around the perimeter of the banjo. When playing the banjo, your right arm rests on the edge of the banding. To prevent discomfort, an arm rest is installed on the banjo just above the tailpiece. The arm rest is a thin wood overlay usually made from hardwood to add aesthetics and functionality to the instrument. You can make your own custom banjo arm rest in about an hour.
Remove the armrest clip from the back of the banjo with a screwdriver. It is held on by one small screw on the side of the banjo.
Lay the walnut on the edge of the banjo with the bottom edge touching the tailpiece. Let the edge of the walnut hang over the edge of the banjo. Use a pencil to trace the curvature of the banjo's outside perimeter onto the walnut.
Clamp the belt sander upside down to a worktable using a hand clamp through the handle of the sander. Turn on the sander. Hold the walnut to the sanding belt. Sand it to the pencil line for the outside perimeter. Turn the walnut around and use the round edge of the sander to sand a slight curve on the inside of the walnut so that you have a very slight boomerang shape. It should have a " ) " shape when you are finished.
Hold the walnut at a 30-degree angle to the belt and sand off the edges. Blend them smooth and round. Round both ends of the walnut with the sander.
Sand the walnut by hand with the 100 grit paper. Continue rounding and blending the edges until everything is round and smooth. Finish by sanding it again by hand with 180 grit sandpaper until it has a dull sheen.
Apply a thin coat of linseed oil to the armrest and wipe it off. Screw the metal clip to the bottom of the armrest and screw it to the banjo. Walnut is an example. You can use any type of wood you like.
Always wear safety glasses when working with wood.