A lock template includes an elongated body member that defines a substantially rectangular first opening having a first length and a first width and an elongated first member. The elongated first member is configured to be removably-inserted into first end recesses of the body such that the first member is located at least partially within the first opening. The first member, when inserted in the first end recesses of the body, defines a wall of a second opening having a length substantially equal to the first length and a width smaller than the first width. The second opening is configured to guide a cutting instrument to form a mortise for a lock component in a passageway component. When the first member is inserted into the first end recesses a longitudinal central axis of the first insert member is offset from a central axis between the first end recesses of the body.