How to Install a Mortise Lockset and Door Knob

Set the mortise lockset against the rail of the door, 36 inches from the bottom of the door. Make the plated edge of the lockset flush with the edge of the door. Trace the lockset with a pencil, and mark the door inside the door knob hole opening.

Continue the traced line of the mortise lockset around to the edge of the door using a combination square. Mark a center vertical line along the edge of the door between the two horizontal lines.

Set the door in a door brace holding the door with the drawn-on edge facing up. Tighten the brace using the clamps on the bottom.

Drill holes to the depth of the mortise lockset into the edge of the door, along the center line between the two horizontal lines. Use a portable drill and a 1/2-inch boring bit for the process. Cut the holes so they are touching at the edges and no wood is left between them.

Drill a hole centered on the marking on the door rail where you had traced the inside of the handle hole earlier.

Draw a line connecting each hole's outer arc, the farthest outer edge of the hole, with the hole next to it. This will make a long oval shape.

Use a chisel and hammer to cut along the pencil marks of the oval shape out of the door edge. Vacuum out any shavings left behind in the oval hole.

Slide the mortise lockset into the oval hole. Trace the outside of the lockset face, the flat metal edge of the lockset, on the door edge. Remove the lockset from the oval hole.

Cut a 1/4-inch layer of the door edge in a rectangular shape on the door edge using the chisel and hammer. Sand the edges of this cutout.

Replace the mortise lockset into the hole, and screw the face into the door edge using a Philips screwdriver bit and the portable drill.

Place the door knob plate on the door rail over the hole drilled earlier for the door knob, and insert the door knob into the hole. Screw the plate into place using the provided screws and the portable drill.