There are two sizes of mortice locks: 21/2” and 3”. If you are installing a mortice lock to a door with a narrow frame, or any door for that matter, it's very important to know what size lock you need. The size of the mortice lock refers to how far the keyhole will be from the edge of the door.
Most backsets are commonly measured at either 44mm (for a 64mm (2½”) lock) and 56mm (for a 76mm (3”) lock). Typically a lock adjacent to a glass panel will be 2½” (44mm) and otherwise 3” (56mm), but you should always measure to be sure.
If the lock is still in the door it is possible to measure from the front plate of the lock to the centre of the keyhole. If the measurement is 45mm, you need a 64mm (2.5") mortice lock. If the measurement is 57mm, you need a 76mm (3") mortice lock. These measurements are approximate.
Mortise locks are installed into a rectangular pocket cut out of the edge of a door. The term mortise refers to a hole or recess cut that allows the lock to be inserted. Mortise lock bodies look much different than cylindrical locks and allow for more working mechanics inside.
Generally, the minimum door thickness requirement for mortice locks/latches is 35mm although some heavy duty types will require doors to be 45mm or over. A lock should have strength at least equal to the door on which it is fitted. Such fitting must not weaken the door in order to accommodate the lock.
There are two sizes of mortice locks: 21/2” and 3”. If you are installing a mortice lock to a door with a narrow frame, or any door for that matter, it's very important to know what size lock you need. The size of the mortice lock refers to how far the keyhole will be from the edge of the door.
Standard Door Measurements
Lock Bore The diameter of the hole for the lock body. The standard bore is 2-1/8”. Many older doors had bores that were been smaller. Most of the current locks require the standard 2-1/8” bore.
A pin-tumbler mortise lock is the most common type of mortise lock available. These Locks are very simple to operate and are fairly inexpensive. However, they are easily picked and are less secure than other types of locks. They are commonly found in older homes and apartments.
Here are the most common ones: Tubular Mortice Latches – these are by far the most common. They have a sprung nib which is operated by turning a door knob or handle. They come in 'Standard' or 'Heavy' sprung versions.
Are mortise door locks universal? Yes, a mortise lock set and mortise door lock is universal and can easily be used to replace most other lock sets, especially on an older door.
Normal mortise view. The entire mortise joint space should be of uniform width, ≤4 mm (light gray). The distal tibiofibular joint (dark gray) should be only slightly wider than the mortise joint space, ≤5.5 mm. The tibiofibular overlap should be >1 mm on the mortise view.
Generally speaking, the width of the mortise should be one-third of the thickness of the stock, but you do have some latitude. If you are going to use a router to cut your mortises, you'll need to find out what router bit you have that is the closest to that thickness.
Measure from the outside edge of the door (including furniture) to the centre of your door. This is dimension A and is called the External Size to Centre. Next, measure from the inside edge of your door (including furniture) to the centre of your door to find dimension B, the Internal Size to Centre.
However, you will find them very easy to handle and a joy to use. Now available in sizes 1/8" - 1/2" by 1/16". It is perfectly acceptable to just have one mortise chisel ( 1/4" or 3/8" being the most common) and size all your mortises accordingly.
Mortice locks are generally available as either a deadlock or sashlock. A deadlock is operated by a key only and is sometimes used alongside a Nighlatch to provide additional locking in the centre of the door. You don't need to use a handle with a deadlock, turning the key or thumbturn retracts the centre deadbolt.
Mortise Locks
There are many different types of mortice cylinder locks, including three lever mortice locks and five lever mortice locks. The number of levers in a mortise lock tells how many points the door locks into the frame. The more levers it has, the more secure it will be.
Whether your lock is broken and needs replacing or you're just ready for an updated look, mortise locks are generally simple to remove and replace; standard mortise lock replacement parts made by Emtek, Juralco, Pado, Papaiz or new-style Wright are easily interchangeable.
Types of mortises and tenons
Haunched mortise. Open mortise. Stub mortise.
Price. Mortise locks cost more because they are more durable, secure and offer more functions than cylinder locks. Plus they come with extra installation costs. On the other side, cylinder locks are more economical and convenient for locations with minimal security needs.
The standard hole size for cylindrical locksets is 2 1/8″. Cylindrical is the most common type in residential settings. The standard backset (distance from the edge of the door to center of hole) is 2 3/8″ or 2 3/4″, with 2 3/8 being more common. Most locksets have an adjustable latch that can be used for both.
The Deadbolt Lock (Cylinder, Round Cylinder) has a diameter of 2.48” (63 mm), front depth of . 53” (13.5 mm), and latch depth of 1.18” (30 mm). The Deadbolt Lock (Cylinder, Round Cylinder) is a common door lock consisting of a cylindrical profile and housing a standard round cylinder.