Adding a Key Lock to a Sliding Door in Botany

Usually, yes — but not by drilling a hole in what is already there. Most sliding door handles are made in both a keyed and a non-keyed version of the same body, so the fix is normally swapping the whole unit for its keyed twin. Whether that twin is still made for your door is the real question, and it depends on the brand and the age of the door.

Because the lock had to be matched against the old one in person. The mortise depth, the fixing centres, the backset and the keeper in the jamb all have to line up, and a tape measure does not settle it. The first visit was to take the old lock off; the second was to fit its match. That is the honest way to do it — the alternative is guessing and then drilling new holes in a door that did not need them.

You can measure, and sometimes it works. But sliding door hardware has a lot of near-misses — parts that are three millimetres out, or have the screws in a slightly different place. A near-miss means packing, filling and a visible repair. Carrying the old part in takes one extra visit and removes the guesswork.

This one was $250 with the lock included, across two visits totalling about two hours. The lock itself is the smaller part of that; most of it is the matching trip and the fitting. A door that needs a lock that is no longer made costs more, because the alternative is a different unit and some adaptation.

It changes what you can do with it rather than making the door itself stronger. With a key you can lock the slider behind you on the way out, which a non-keyed handle simply does not allow. The glass, the track and the frame are unchanged — if you want the door itself harder to force, that is a different conversation about the door, not the lock.

Yes, unless you want it gone. It gets handed over with the keys — a working non-keyed handle is worth keeping in a drawer if the same door, or an identical one elsewhere in the house, ever needs a part.