Surface cadmium plated per qq-p-416, 3 radiating arms 2.499in. Od, 1.563in. Id for 3.990in. Then 1.603in. Max, 4.852in. L, 15splines on id of hub 0.377in. Apart, 11.542in. O/a l, cone seat surfaces not plated, spider must balance in all positions about cone seat axis