The shaft diameter is 7/8" (0.875 inches); this 5 HP model uses a reinforced shaft larger than the standard 5/8" typically found on lower-power 56-frame motors.
The "56" designation refers to the mounting base dimensions and the 3.5-inch shaft height, allowing it to fit standard compressor mounting brackets.
The shaft length is 2.25 inches, requiring a pulley or coupling with a 7/8" bore and a 3/16" keyway.
By vevor
