Half Mortise Lock Information

Half Mortise Locks are a popular style, frequently used on 18th & 19th century antique furniture. Lock-mechanism fits into a notched area in wood, Once installed only lock-plate is visible from furniture interior.
Use on Drawers, Doors and Boxes.
Drawer Locks were commonly used on drawers. Lock-bolt shoots up into case above drawer, a strike is rarely used.
Door Locks are handed meaning right-hand or left-hand. Please note: some half mortise locks are not available in both left and right options. When looking for door locks be sure lock is handed according to your needs.
  • doors hinged on right - bolt shoots to the left.
  • doors hinged on left - bolt shoots to the right.
  • Measuring half mortise locks
    Lift-lid Box Locks require a special strike with notch clips to drop down and catch in lock

    Measuring Half Mortise Locks:
  • Before looking for a replacement it will be necessary to measure your lock.
  • Please view diagram below to determine how to measure your lock.
  • The backset measurement, is the most important measurement, must match precisely.
  • Once the backset measurement is determined you can look at your various options.
  • If potential substitutes have different lock-body or lock-plate measurements cabinet work may be necessary to fit the lock.
  • Measuring half mortise locks
    Installing Half Mortise Locks:
    Determine desired location of lock
  • Adjust position to allow for location of keyhole as it is often off center in lock
  • Mark location of lock on drawer or door interior
  • Hold lock at desired location against drawer or door interior
  • Selvedge edge should be level with top of drawer or edge of door
  • Trace outline of lock on drawer or door interior
  • Trace outline of selvedge on drawer top or door edge
  • Inspect outline for accuracy , straighten lines where necessary
  • Mortise lock-plate, Selvedge and lock-body
  • Again holding lock in position, trace lock-body
  • Cut shallow mortise for lock plate and selvedge with router or chisel
  • Selvedge and lock-plate should be flush with the interior wood surface once installed
  • Cut lock-body-mortise. Okay if off slightly as lock-plate will cover lock-body once installed. Be sure there is ample room for mounting screws to attach lock
  • Use of a strike is rarely necessary on drawers and doors. Traditionally a simple mortise was cut in the wood to accept the lock bolt.
  • Notched strike is necessary for boxes and chests with lift lids
  • 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
  • For a finished appearance: mount an escutcheon/keyhole plate, on furniture front.
  • If Using Strike (for box locks)
  • Align strike on underside of lid
  • Trace outline of strike in position
  • Check strike alignment and make adjustments if necessary
  • Screw into place
  • Close