Cutting a square hole with a wood chisel is not rocket science, but a simple, straightforward procedure. To get the best results, you will have to make surgically precise cuts with a razor-sharp chisel. You will regulate the size of your hole by choosing the proper chisel size -- for example, a 1/2-inch chisel cuts a 1/2-inch square hole. Learning this cutting technique will help you make better hobby crafts, as well as work more easily with door and jamb installation and mortise and tenon joints.
Draw a 1/2-inch square on a piece of wood with a tri-square. Mark two lines 1/2 inch apart across the wood perpendicular to the grain. Then draw two lines 1/2 inch apart across the wood parallel to the grain, intersecting the first two lines, to make a perfect square.
Place the sharp edge of the chisel on one of the lines running perpendicular to the grain. Tap on the end of the chisel with a hammer to make a 1/32-inch deep cut into the wood. Place the edge of the chisel on the line running parallel to the first and make a 1/32-inch deep cut there.
Place the chisel on one of the lines running parallel to the grain. Tap and cut it, then the other line, 1/32 inch deep to establish the perimeter of the square.
Place the chisel on one of the lines perpendicular to the grain. Tap harder this time to cut 1/8 inch deep into the wood, then repeat this on the line parallel to the first. Repeat this on both lines running parallel to the grain. Insert the tip of the chisel into one of the cuts to pry the centre of the square up and out of the hole.
Place the edge of the chisel on a line perpendicular to the grain. Tap on the chisel to cut down another 1/8 inch. Move the chisel around the square cutting down 1/8 inch at a time until you reach the desired depth. Continue prying out the centre every 1/4 inch.
Try to hold the chisel as vertically as possible. If your vertical alignment drifts off, you can clean up the sides of the hole later.
Always wear safety glasses. Watch out for the centre of the hole when it pops out.