I just bought a house from the 1920s and all the interior doors are mortise locks with skeleton keys. I would like to change some from key to privacy with a thumbturn. Is there a way to simply convert or do I have to replace the mortise lock to a privacy lock first? My doors do not have backplates/trim plates and the wife doesn't want to add them to the door, but through my research it doesn't look like I can just buy a thumbturn and insert it. Just want to make sure I'm not missing other options. TIA!
Mortise lock conversion from key to privacy
lockmortise
Best Answer
I've done that for a bathroom recently. I replaced the locks of several doors entirely with this lock (fit like a charm). For the thumbturn, I purchased this plate and thumbturn kit. It required a bit of 'macgyvering' but it turned out well.
I had to combine the thumbturn provided in that kit with the key provided by the lock. The thumbturn provides a handle, a square 'arm' with a hole in it, and a pin which connects the thumbturn and the 'arm'. Luckily the shaft of the key fits in the hole of the thumbturn; by cutting off the handle of the key (to appropriate length) and drilling a hole in the shaft you essentially swap the 'arm' provided with a functioning key. Photo illustrates the result:
The pin portion of this thumbturn contraption is hidden behind the plate provided with the thumb turn. Result works and looks great.