night latch | security door locks

Night Latch door lockA night latch security door locks consists of a cylinder barrel, into which the key fits, and a latch case, mounted on a back plate on the inside of the door.To fit one of these latches you need to drill a hole through the door of sufficient diameter to take the cylinder barrel. Start drilling from the front of the door, using a brace and bit. The hole will probably need to be about 38mm in diameter and should be positioned so that the connecting bar of the cylinder locates correctly into the latch case. The dimension for aligning both part of the door lock are usually given with the fitting instructions. The connecting bar will also have to be cut to a length to suit the thickness of the door. The cylinder passes through the latch pull, a surround that incorporates a small handle with which you can pull the door closed. Screw the back plate into place on the inside of the door, aligning the hole in the plate with the hole in the door. Cut the connecting bar so that it protrudes about 13mm on the inside of the door into the latch case. Screw the latch case to the cylinder. Shut the door and slide the keep on to the night latch. Mark the position of the keep on to the frame, and then chisel out a small recess so that the edge of the keep fits flush. Fix the keep with screws.