Select the angle you need for your job. The 45 degree angle is appropriate for mitering cabinet doors. All miter boxes have this angle for both a left and a right angle cut.
Use pieces of scrap wood to make a test pattern. Cut off 1 inch from the pieces of wood you will join. This gives you a clean surface with no nicks or splinters.
Make a mark on the outer edge of the pieces to be cut. Put a piece of scrap wood under the wood pieces you want to cut to protect the miter box.
Insert the backsaw into the miter box. Support the wood and carefully saw through the wood to the mark. Both pieces will fit together in a perfect 90-degree angle.
Adjust the miter box if necessary and follow the same directions to work on the moulding pieces. Use a utility knife on the backside of the wood to smooth away any splinters.
Stain and dry the finished moulding. Attach the moulding to the cabinet door with finishing nails.