Following up on this question, if you set aside the stick before Shabbos to be used only as a lock and never as a vacuum clearner anymore, would it then lose its status of muktza and would one be allowed to move it?
May one use the stick attachment of a vacuum cleaner as a way to lock a door on Shabbos? Is it considered muktza even if one is using it for a permitted purpose?
The stick attachment of a vacuum cleaner essentially is not used for anything else but vacuuming the floor. Therefore since it doesn’t have any other reasonable use, (most people that I know don’t do things like this with a vacuum cleaner stick) it is considered a li shmilachto l’issur that doesn’t have a heter use, similar to moving a candle if it’s place is needed. There is much controversy among the poskim (see sources) if it is allowed to be moved or not. R’ Eliyashiv ruled that it should not be moved unless it is very necessary.
If it is permenantly designated to be used as a lock for a door, then it is not muktza because it is right now halachically (and by the owner) considered a door lock.
O:CH 308-22, M:B 308-91.