A miter joint is a corner joint formed by cutting two pieces at 45-degree angles so that when joined, they make a right angle. Miter joints are commonly used for picture frames, door frames, and cabinets where you don’t want end grain to show.
Miter joints are best cut in a miter box, either an inexpensive one made of hardwood with 45-degree slots or a metal one that gives greater precision and can be set at other angles. Use a crosscut saw with 8 to 12 teeth per inch for rough work, a backsaw with 13 or more teeth for finer cuts.
Mark the cut line on the wood with a combination square. Brace the miter box with its lip against a bench edge, place a piece of scrap wood in the box, and put the piece to be cut on top of the scrap, right side up. Hold the piece against the far side; align the mark with the 45-degree slot so as to cut just on the waste side of the line. Make gentle pulling cuts at the far edge; when the cut is established, saw with smooth, pushing strokes. On a wide piece, make a second pulling cut at the near edge; then alternate between the cuts, making the final strokes in the center.
Cut the adjoining piece with a 45degree cut slanting the other way. Check the joint for squareness. Glue the cut ends and clamp them in a spe cial miter clamp. To strengthen the joint, drive finishing nails into the glued pieces from each side; in hardwood, drill pilot holes first.