Abstract: A mold locking system is provided for a glass molding machine. The machine has first and second mold hanger support arms for moving respectively first and second mold halves. The arms are pivotally cantilever-mounted at their ends for rotation about a vertical axis between a retracted station where the mold halves are separated and a forming station where the mold halves are brought into contact. The locking system includes a pressure system for exerting an upward force on the free ends of the support arms and includes surfaces configured to pressingly engage specially configured portions of the free arm ends so that operation of the pressure system forces the free ends towards each other to ensure closure of the mold, and to force the free ends up against a limit stop to terminate upward travel to compensate for sag and mounting system wear.