Lock Replacement & Upgrade: preparing for the visit

The century home's original mortise lock takes a key the size of a spoon, sticks in humid weather and has worn its strike to a groove. You want a lock that works every day without giving up the old door.

Worth answering before the call

Which doors are you thinking about, and what is on each one now? Can you photograph each lock from outside, inside and along the door edge? Has the door been forced or damaged, or does it need a push to lock?

My old house has a mortise lock. Can it take modern hardware?

Often the original case can be kept and given a new cylinder and strike, which keeps the period look and the old door intact. Where the case is beyond service, a filler or conversion plate covers the mortise pocket and lets a cylindrical deadbolt or knob set be fitted without cutting into the door's stile. The locksmith looks at the door before recommending either path, since old doors vary a great deal.

What does a higher grade of lock actually give me?

Grades follow ANSI/BHMA standards, with Grade 1 the highest and Grade 3 the lightest, and residential hardware carries a separate label that scores security, durability and finish. The grade reports how the lock performed on the standard's own operational, strength and security tests; a higher grade often comes with a longer bolt, a sturdier housing, pins that resist picking and a strike built to anchor into the framing, but those features are worth confirming on the specific model rather than assumed from the grade alone.