I have two external mortise lock doors that will only open with skeleton key. After several years I'm ready to upgrade. Will I have to get a new door or can I upgrade these to modern locks. I've searched the internet over and I'm either not using the correct terminology. All I can find it swapping out for new mortise locks. Not interested in that at all.

Any help is appreciated.

  • Contact a local locksmith. Ask them if it is possible, cost of how much, time involved and what brand/model they will use. Sometimes it makes since for professionals to do a job, other times just need the professionals to point you to the right material.
    – diceless
    Sep 23, 2014 at 20:04
  • It is incorrect to contrast "mortice locks" with "modern locks". In my (reasonably modern, first-world) locale, insurance companies encourage householders to fit 5-lever mortice deadlocks. When applying for insurance the form explicitly asks if I have a mortice lock fitted or not. Sep 24, 2014 at 9:57

2 Answers 2


There are certainly modern mortise locks which accept pin-tumbler cylinders. Whether any of them will fit in your existing mortise is another question; you may need to enlarge the mortise. You will undoubtedly have to drill for the cylinders; you may need to drill new knob/latch holes as well (though "decorative" brass or chrome plates can hide a multitude of sins).

If you want to switch to a "cylindrical" design (typical modern knobset, mechanism is housed in the knobs and a cross-bore rather than in a mortise), or a rim (surface-mount) lock, you'll either want to leave the old mortise lock in place, or glue in a block cut to exactly fill the space it occupied, since otherwise the empty space would weaken the door. Same issue exists regarding old holes in the door faces; same solution applies.


My step father recently undertook this project. He started by removing the old lock mechanism. Then he filled the space previously occupied by the lock, with a solid wood block. Next he used some form of wood filler (not sure the exact brand/type he used), to fill the holes in the faces of the door. Once he painted the doors, they looked like new. He finished by drilling new holes in the door for the replacement handles.


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