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.
were commonly used on drawers. Lock-bolt shoots up into case above drawer, a strike is rarely used.
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.
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.
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
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