What is a full-mortise lock? 

For new furniture, check that the wood is thick enough to accommodate the lock body. Choose the lock before cutting the pocket or making the keyhole, so both can be positioned to suit the lock.

When replacing an existing lock, match the backset first. This measurement determines whether the keyhole in the lock lines up with the existing keyhole in the furniture. Then compare the lock body dimensions with the existing pocket. The wood pocket may need to be reworked to accommodate the replacement lock.

New Construction

• Consider placement of keyhole cover on drawer, chest or box as this could affect actual keyhole location
• Keyhole location determines required backset measurement for lock.
• Backset: distance between selvedge-edge of lock to center-of-pin in keyhole. (see diagram above)

Replacing locks:

• If you have original lock: measure distance between top edge of lock to lock pin in center of keyhole. This measurement is known as the backset.
• If old lock not available, determine backset by measuring: distance from center of keyhole (where lock pin will be) to top-edge of drawer / box or side-edge of door.
• The backset measurement of the replacement lock, must match backset measurement in original lock and/or keyhole location measurement in drawer, box or cabinet door.

Determine desired location of lock

• Adjust position to allow for location of keyhole as it is often off center in lock
• Lock should be positioned in middle of wood thickness, providing a wood edge around selvedge
• Mark location of lock-selvedge on door or drawer edge
• Hold lock-selvedge, at desired location, on wood thickness and trace outline
• Inspect outline for accuracy , straighten lines where necessary
• Mortise Selvedge

Lock-body

• Trace lock-body outline into selvedge-mortise at correct position
• Cut lock-body-mortise
• Mortise can be slightly off as selvedge will conceal lock-body once installed.
• Check lock with mortise, lock should sit in mortise with selvedge flush with wood surface
• Strikes are rarely use with reproduction full mortise locks. Traditionally a simple mortise was cut in the wood to accept the lock bolt.

Keyhole Placement

• Measure distance from top of lock-plate to center of key pin
• Measure distance from side of lock-plate to center of key pin
• With these two measurements locate keyhole on furniture front, make sure key pin is aligned with keyhole location
• Drill small pilot hole at key pin location, hold lock in position and check to make sure hole lines up with key pin
• Drill hole larger to accommodate key barrel

Mount Lock

• Mount lock in a mortised- pocket in wood thickness/edge
• Selvedge edge should be level with top of drawer or edge of door
• Attach with wood screws
• For a finished appearance: mount an  escutcheon/keyhole plate, on furniture front.