BB mortise lock - forend width 20 mm

Backset (in mm)

Is the distance from the centre of the lever handle or lock cylinder to the front edge of the forend.

Distance dimension
Is measured from the centre of the lever hub or turning knob to the centre of the cylinder recess (keyhole). This measure is standardized in Germany with the following dimensions:

• 72 mm for interior apartment doors
• 78 mm WC - doors
• 92 mm front doors / apartment doors outside

Square spindel

• square spindel 8 mm
  interior apartment doors, room doors
• square spindel 9 mm
  fire door and doors with panic locks
• square spindel 10 mm
  special doors, exterior doors

Forend width and length
The forend is the front face of the mortise lock which is visible after installation in the door. The design of forend can be rounded or square.

The DIN direction of the door alignment is also important for the selection of the mortise lock. A distinction is made here between DIN right and DIN left. If the door hinges are on the left-hand side when the observer looks at the closed door, this is a door with a DIN left alignment, if the door hinges are on the right side, this is a DIN right door alignment.

Rebated door

The most used door is the rebated door. In it, the rebate is a small step at the edge of the door leaf. As a result, the door leaf rests on the frame. A seal on the frame (door frame) provides the necessary sealing and soundproofing.

Non-rebated doors

Doors without a rebate are called non-rebated doors. Architects often require a harmonious and flush finish between the door leaf and frame. This is achieved by non-rebated door leaves. Due to the flushness of the frame and door leaf, it is an absolute eye-catcher in the room.