is termed "open joint hanging," from the fact that when the door is open a certain amount of open space exists between the edge of the door and the doorpost. This open space varies according to the position in which the butt hinge is fixed. A section is shown at which the pin of the hinge is let in level with the face of the door. This will allow the door to o
indicates the position of the hinge fixed so as to allow the door to open and lay flat back to the architrave moulding. In this instance the butts are made with wider wings, and they are generally provided to take three screws (see , right-hand wing of hinge).
To determine the position of the centre pin of the hinge the following rule is observed. The centre of the pivot pin of the hinge must be half the distance between the face of the door, when closed, and the outside of the architrave moulding.