Re: trying to replace old sargent single bolt deadbolt
Unless you can find another lock of the same exact brand and design, you're not going to be able to reuse the knob because it will be incompatible with anything else. If you're referring to having to replace the door knob independently of the deadbolt system, that should not be the case, unless the handset also has a locking mechanism and you want the locks to be keyed alike.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!