How to Cut Miter Joints With Hand Tools

Stretch a tape measure across the molding. Mark the overall length of the cut with a pencil. Place the 45-degree angle side of the combination square over the mark. Run a pencil along the edge of the square to lay out a line across the width of the molding. If your miter box accommodates another type of angle, use a compass set to the proper angle, rather than a combination square.

Place the molding in the interior of the miter box with the mark facing up. Butt the molding against one side of the box and align the molding's mark with the slits that cut the desired angle. If you drew your layout lines correctly, the mark will align with a slit on both sides of the box.

Hold the molding in position with one hand and pick up the backsaw with the other. Insert the backsaw into the slits that align with the molding's mark. Rest the backsaw directly atop the mark.

Draw the saw slowly across the molding to begin the cut. Cut lightly to form a small groove through the molding's mark. If you take your time to develop this groove, the saw will not slip out of place when you cut with more force.

Saw with increased force as the backsaw cuts deeper into the molding. Slow your cutting pace as you reach the opposite side of the molding. Finish the cut with gentle strokes to avoid creating splinters.