I'm trying to replace an old brass door knob. I've replaced others in
the house but this one won't budge, it's stuck on the square rod that
goes through the door to the handle on the opposite side. I can see no
screws attaching either door handle to the square rod. Brute force isn't
working, am I missing a trick here? The lock is one of those that has
the mechanism in a rectangular metal box screwed to the door.