How to Install an Interior Door Mortise

Mortising a door before installing ensures that the door will fit into the frame properly. To mortise a surface, you carve out a space for hardware installation. When discussing an interior door, the hardware involved would be the hinges and the latch set. Mortising allows each piece to sit flush with the door, creating an even, smooth surface. You literally make the hinge and latch part of the door to enhance the look and create an entryway that functions smoothly.

Things You'll Need

• Tape measure
• Utility knife
• Hinges
• Mortise chisel
• Medium-grit sandpaper
• Latch set
• Drill
• Screwdriver

Instructions

Hinges

1. Measure and mark the locations of the hinges. The old door will be the best guide. Lay the old door down on a flat surface. Use a tape measure to determine the location for each hinge. Once you note the measurements from the old door, move to the new door. Use a utility knife and scribe a line for each piece of hardware.

2. Lay the first hinge on the new door at the marked spot and trace the outline of the hinge with a utility knife. Run the knife around the outside of the hinge and scar the door surface, creating the outline of the hinge.

3. Butt the hinge against the edge of the door. You need to mark the depth of the hinge. Line the end of the hinge directly beside the edge of the door, where the hinges will attach. The hinge and the door edge should be parallel. Run the utility knife under the hinge to mark the depth. The marking will be on the inside edge of the door.

4. Repeat this marking process for each hinge.

5. Take a mortise chisel to the marking for the first hinge. Hold the tool at a 45-degree angle with the beveled side pointing toward the surface of the door. Set the chisel along the grove of your outline, pointing inward. Tap the chisel with a hammer until the end of the chisel meets the depth marking for your hinge. Imagine sculpting. You tap the chisel to sculpt the hinge image into the door, removing the debris as you go.

6. Lift up on the chisel, move it approximately one-quarter inch along the outline and repeat the process. Continue moving the chisel until you score the area for your hinge.

7. Repeat this process for all the hinges.

8. Sand down the mortised area with medium-grit sandpaper until smooth.

Latch

1. Measure the old door and mark the location for the latch bolt and plate on the new door, scoring the door with the utility knife. This area is flush with the door frame and holds the door closed.

2. Repeat the mortise process using the door latch bolt as the guide. Score the bolt area with the utility knife. Cut the outline and mark the depth. When mortising the latch bolt, lay the bolt on top of the door surface and score the depth from the outer edge. If you consider how the latch sits in an installed door, you should be able to visualize the process. Once marked, mortise the inside edge of the door with the chisel following the same technique used for the hinges. Sand down the mortised area with medium grit sandpaper.

3. Drill holes for the latch plate. The plate goes on the inside of the door and surrounds the area chiseled for the bolt. Make the plate vertical with the door edge.

4. Temporarily install the latch plate. The alignment of the plate is crucial. By securing it, you can prevent it from moving.

5. Score the area around the plate with the utility knife and then unscrew the plate and remove it. Chisel the shape of the plate into the door and sand it down.

References

• Ace Hardware: Installing Hinges
• Ron Hazelton's HouseCalls: How to Install an Interior Door

Resources

• Read this Article in Spanish