How to Make a New Key for an Old Mortise Lock
Create a fresh key to open all the antique locks in your house
Q: Our old doors still have their antique locks, but no keys. Can I get keys that work?
—Margaret Cowie, Stark, N.H.
Master locksmith Larry Cosares replies: Of course you can! And, most likely, one key is all you'll need because interior doors on old houses typically share identical locks.
The first step is to remove one of the locks and take it in to an antiques store or a locksmith that has a collection of old bit keys, often called skeleton keys. If you're lucky, you'll find a key that actually slides into the keyhole and throws the bolt, and your quest will be over.
If not, look for a bit-key blank that's a close fit, and follow the steps shown here to cut the key so that it operates the lock. It's a simple job with a nice reward: bringing an old lock back to life.
Shown: TOH senior technical editor Mark Powers had this bit key made to get his old door locks working again.