Crafting Replacement Keys for Vintage Mortise Locks

Owners often wish to keep mortise locks because of their distinctive style.

Older buildings frequently contain mortise locks, and these are commonly refurbished for their build quality, antique worth and vintage appearance. The term "mortise" refers to the pocket cut into a door to accommodate the lock mechanism. Since cylindrical locks became widespread, the mortise design now appears most often in higher-end or commercial buildings where locks are rekeyed regularly. Some mortise locks are over a century old. Many were equipped with skeleton keys or simply designed keys that most locksmiths can readily swap for a master key. You can replace the cylinder on your own to obtain a new key, or fabricate a replacement key yourself.

Step 1

Inspect the old mortise lock closely for a manufacturer's name and model number. Look for brands such as Corbin P series (P1 to P12), Brinks, Baldwin or Sargent & Co.

Step 2

If you can determine the manufacturer, search online for replacement parts offered by lock companies or individual sellers. Should the manufacturer remain unidentified, carefully unscrew the lock from the pocket to open it up.

Avoid attempting to open an old mortise lock on a locked door with grinding tools, since this may shatter your grinder. A locksmith can pick the lock and open it without damaging your door or the lock, and can then rekey it.

Step 3

Switch your mortise lock to a modern lock using a conversion backplate kit, which comes with instructions and all components, including a key. If the old lock will not unscrew, you may need a locksmith to remove it before you install the conversion kit yourself.

Step 1

Create your own hand-filed skeleton key. Take off the mortise lock's panel to access the locking mechanism. Study the lock carefully, as each one differs.

Step 2

Detach the keyhole from the lock and clamp it in a vice. Use a metal saw around the keyhole to reach the metal casing. Observe the key pattern to identify all the standing pins that control the lock. Remove only the top set of pins, working carefully.

Step 3

Push a blank skeleton key through the keyhole and onto the bottom set of pins. The bottom pins will rise through the keyhole.

Step 4

Make a key by placing the original key or a skeleton key on a flat piece of tin. Trace its outline onto the tin. Cut the tin out with heavy-duty scissors. Clamp the keys together in a small vice. File the tin into the shape of the original key and refine it until the tin key fits into the mortise lock.

Step 5

Use a metal file to file down the skeleton key or tin key until all pins lie flat at the top of the keyhole. Continue making small adjustments with the file until the key fits perfectly.