Product Description Specifications Documentation P8H Heavy Duty Shaft. 5/8in diameter x 3in long made from 4142 hardened alloy with an 1/8in keyway and a #10-32 end tap.This shaft will only work in a P8H Heavy Duty gearbox with a P8H Heavy Duty Front Block. Diameter: 5/8 in Length (From Face): 3 in Keyway: 3/16 in End Tap: 1/4-20 Material: 4142 Hardened Alloy Click arrow in center of image to load and interact with it Your browser does not support iframes.