Door Lock Backset Measurement

Please see the demonstration below.

Door lock backset measurement.

Pack your locks with a 2 3 8 inch or 2 3 4 inch latch depending on which backset you specify. In the united states there are two common backsets for residential door locks. The most common sizes here are 44mm on a 64mm 2 5 lock case and 56mm on a 76mm 3 lock case. This is very important when replacing locks because you don t want to have to drill new holes if you can help it.

There is a range of backset long body locks at 20mm 25mm 30mm 35mm 40mm 50mm and 70mm. Two standard backsets are 2 3 8 and 2 3 4. Mortised latches come in a radius corner rounded on the edges or a squared corner configuration. Dead bolt latches top 2 3 4 bottom 2 3 8 note.

Falcon used to make a 5 backset that would work with emtek hardware but i believe it is no longer available. To do this measure the backset distance of your old lock. The backset measurement is the distance from the centre of the keyhole to the leading edge of the lock. Almost all domestic mortice locks and tubular latches are supplied with either a 44mm or 57mm backset length.

The backset is the distance from the edge of the door to the center of the 2 1 8 inch bore hole. In the uk and much of europe these dimensions can vary from 25 to 60 mm and many medallion knobs are placed in the center of the door creating a very large backset. The most common backset is 2 3 8 but 2 3 4 is also quite common usually used on exterior doors. Most commercial doors have a backset of 2 3 4 inches 69 8 mm while residential doors measure 2 3 8 inches 60 3 mm.

These smaller backset sizes are generally european and some are still in use today. Other backsets include 2 used by national and lori lock and 5 used by weiser weslock kwikset and others. Standard backsets are either a 2 3 8 backset or 2 3 4 backset. Sometimes it s easier to measure from the edge of the door to the highest point on the bore hole.

2 3 8 inches and 2 3 4 inches. If you dont have any hardware on your door just measure from the edge of the door to the center of the bore hole the large hole where the door knob assembly is mounted. Backsetthe distance from the edge of the door to the center of the lock bore. The backset is measured by placing a tape measure or ruler from the center of the keyhole to the forend of the mortice lock.

These equate to case sizes of 2 1 2 or 3 in imperial measurements. Some older residences will have variations to installed locks.