How to Fit a Mortise Lock

Fitting a mortise lock, mark the center of the middle rail. This is the position in this door where the lock would be fitted. Square around onto the edge of the door. Now find the middle of the mortise lock and mark up with a pencil. Match these two lines up then mark the top and bottom of the lock onto the door. Draw around the profile below according to the face of the door. There are many different types of mortise locks available some suitable for internal doors and some for external.

Again as with the cylinder lock, it’s advisable to consult your insurance company before fitting. After transferring the portion of the door that needs to be chopped out, find the central line and mark. Use a flat bladed wood bit slightly larger than the width of the lock mechanism. Wrap a piece of adhesive tape around the bit at the depth of the hole that needs to be drilled. Carefully drill them the marked position of the door removing the section that will fit the mechanism.

Square up the hole, chiseling it out with the wide bladed chisel. When this has been completed, clean up with a smaller chisel and try to lock. Draw around the edge of the lock and remove enough of the wood to accommodate the lock face. Once you have done this, check that the lock fits. Now place the lock on the front of the door and mark the position of the handle and keyhole. Drill this out on both sides of the door. Use a smaller drill to give you the position to drill from on the other side.

As the keyhole has a rectangular shape, drill two holes and then tidy up with a chisel. Now fit the lock into the door. Push the spindle through the lock mechanism. Position the door handle. Square up then fix to the door. Now check that the lock works. Close the door moving the door backwards and forwards. This will mark the door frame where the key will need to be fitted. Position the key from the door frame. Drill around the sections that need to be chopped out.

Chisel this out with a suitable size chisel remembering that the lock and large area need to be quite deep. Check that the key fits correctly. Drill the pivot holes and fix. The catch plate will need to be bent slightly in order for the door to open and close properly.