Hanging a door into a door jamb is a straightforward process if the mortises for the hinges have already been cut into the jamb and the door. Traditionally, the task of cutting the mortises for the hinges was done with a sharp chisel and a hammer. However, technology has made this task much simpler, quicker and more consistent. With a router, you can easily create the mortises to hang a door with a hinge jig.
Position the door so the edge to receive the hinge mortises is pointing upward. Determine which way the door will open, as the hinge pins will be on the side to which the door will open.
Measure down 5 1/2 inches from the top along the edge to receive the mortises and make a pencil mark. Also measure up 9 1/2 inches from the bottom and make another pencil mark. Finally, measure the distance between the two marks.
Align a hinge jig so the top of the jig is aligned with the top pencil mark. The jig should protrude over the edge of the door on the side that the hinge pins will be located. Secure the jig to the door with two pan head screws.
Install a 1/2-inch straight-cutting bit and a guide collar into the router. The bit should protrude down 1/8-inch below the collar.
Turn on the router. Insert the router bit and collar into the jig and follow the jig with the collar until the entire mortise is cut. Remove the router from the jig and turn off the router. Remove the two screws and the jig.
Repeat Steps 3 through 5 with the jig positioned just above the bottom pencil mark.
Measure down 5 5/8 inches from the top on the side of the door jamb to receive the mortise and make a pencil mark. Measure down the jamb the distance between the two pencil marks you determined in Step 2 and make a second pencil mark.
Repeat Steps 3 through 5 to cut the two mortises in the jamb.
Square the two rounded corners of each of the four mortises with a sharp chisel.
Position the two hinges into the two mortises on the door and attach to the door with the screws that came with the hinges.
Position the door into the jamb so the two hinges are aligned with the mortises and attach the hinge to the jamb with the wood screws that came with the hinges.
Test the door by opening and closing it. The reveal around the door should be even all along each of the four edges of the door.
When using a router, always wear safety glasses to protect your eyes from flying debris. Also use hearing protection.