How to Make a Siding Jig for HardiePlank

Cut two pieces of 1/2-inch-thick plywood to 1 inch wide and 3 inches long. Measure the width of the HardiePlank siding and subtract 1/4 inch to obtain the jig height. Cut a third piece of 1/2-inch-thick plywood to 3 inches wide and as long as the jig height.

Lay a 1-by-3 piece of 1/2-inch-thick plywood along the 3-inch-wide end of the longer piece with the two 3-inch-wide edges flush. Screw the 1-by-3 piece to the longer piece with two 1-inch drywall screws. This is the bottom end of the jig.

Turn the jig over. Mark the end opposite the 1-by-3 piece at 3/4 inch from the end. Lay the combination square on the piece with one leg against the side and the other leg aligned with the mark. Draw a line across the piece.

Lay the second 1-by-3 piece of 1/2-inch-thick plywood on the opposite end of the longer piece with the 3-inch edge aligned with the line. This leaves it overlapping the end by 1/4 inch. Screw the piece to the jig with two 1-inch drywall screws. This is the top of the jig.

Cut 1-by-2 lumber to 3 inches long. Place the narrow edge against the middle of the jig so it runs from side to side, on the same side as the 1-by-3 piece that overlaps the jig end. Hold the piece in place and screw the jig to the 1-by-2 from the other side using three 1-1/2-inch drywall screws. This piece is the handle.