– Lock bore: refers to the diameter of the hole on the door for installing the lock body. The standard bore for most of the current locks is 2-1/8”. If you want to replace it with locks has smaller diameter holes, re-drill the door or look for custom lock cylinder manufacturer to make suitable locks.
– Lock spacing: the distance between the upper and lower lock on the door, measured in the length of two centers of the holes. When boring deadbolt locks in a door, there are two common standards for spacing between the bottom lock and the deadbolt, they are 5-1/2” and 6” from the centers of the two holes. There are other combinations of lock spacing for specialty locks.
– Backset: the distance from the edge of the door to the center of the lock bore. Standard backsets are 2-3/8” and 2-3/4”. Other options include 2” and 5”. When replacing locks, the latch backset needs to match the holes bored in the door.