Recessing
With the lock fully inserted into the door, use a sharp pencil to draw a fine line around the forend. Remove the lock, and re-define both vertical lines using the marking gauge. The top and bottom horizontal marks can also be defined using a square set to the face of the door.Using a sharp chisel, recesses the rectangular area to a depth equal to the thickness of both the forend and the faceplate of the lock.
Marking The Keyhole
Now that the lock fits into the door, the position of the keyholes must be marked by position the lock (with the faceplate attached) onto the door between the two lock case horizontal lines, so that the front of the faceplate is flush with the edge of the door as shown in Fig 7. With the lock held in this position, use a bradawl to mark the top and bottom of the keyhole, and using a square, draw short squared lines to the top and bottom of these marks. In addition to this, draw two additional short lines to the edge of the door, and transfer them around the door edge to the opposite face. Set the marking gauge from the faceplate of the lock to the centre of the keyhole and join up the two keyhole marks with vertical lines on both faces of the door.
Handy Tip
Before boring holes into the door to form the keyholes, insert a piece of wood about the same thickness as the lock case into the mortice first, this will prevent the damage to the inside of the mortice.
