Backset
Backset is the distance from a door-edge datum to the lock operating centre or specified bore centre. Confirm the datum used in the manufacturer's drawing before reading the value.
Dimensions and compatibility
Understand backset, door preparation and door thickness, including measurement reference points and drawing checks.
Door-lock bore holes
Lock preparation includes the main bore through the door face and the bore from the door edge. Distinguish their positions when reading bored-lock documentation.
Door closer arm types and installation conditions
Standard arms, slide arms, hold-open arms and parallel-arm mounting describe different constructions or configuration relationships. When selecting a closer, confirm arm type and mounting method together with door width, weight and body model.
Compatible door thickness
Compatible door thickness is the range of leaf thicknesses supported by a complete lock and its mounting accessories. Check it against the actual door and configuration.
Padlock shackle diameter and opening dimensions
Shackle diameter describes the thickness of the bar passing through the hasp; opening dimensions describe the space available inside the shackle. Both differ from lock body width and should be checked separately.