Posted by Ed Donaldson on 8/5/2020 to Questions
Question - If I have a lock that uses a bit key, can I exchange the key for a latch thumb turn?
I can see how having a "key' in a bathroom door that isn't removable would come in handy, especially with rug rats around! The initial answer to this question is no, but I am never one to leave things alone. A key has a bit on one end that moves the bolt to the locked position. A latch thumb turn ends in a square shaft, and a privacy latch has the 'bit' included within the lock allowing the thumb turn to fit into a cavity within the "bit".
I know of two fixes for this. One is to cut the length of the key so it just protrudes from the door. The second would be to find a thumb turn and join the two pieces together. The joint doesn't need to be that neat since it will be hidden within the door but the length is critical so the back plate of the thumb turn fits against the door while the key works well in the lock.
Enclosed is a photo of four keys used with rim locks that were made for this purpose. They are short keys that won't fit thru the door but are used a a 'turn' on the inside. Also, did you know leaving a bit key in your lock and slightly rotating it makes a lock almost impossible to pick from the outside.