Flange screw joints are used as a rule for the connection of lines on hydraulic pumps or hydraulic motors. They seal using an O-ring or sealing sleeve on a level contact surface of the pump or the motor clamped on the flange using screws. The connection to pipes or hoses is done via cutting ring screw connections or female threads. A distinction is made between flange screw connections with square hole pattern (here the hole circle of the fastening holes of the flange are critical: 35, 40 or 55 mm) or flanges with SAE hole pattern 3000 PSI / 6000 PSI. SAE flanges are mainly clamped with special SAE flange halves on the level contract surface using screws.