Second step from first end is splined
A shaft having two or more different diameters (greater than 0.031 inches (0.79 millimeter)) along its length. It must have one or more of the following conditions: a specified surface finish designation in the range 1 to 125 microinches (0.025 to 3.2 micrometers) arithmetical average (aa), machined peripheral flat(s), circular groove(s), keyway(s), splines, threads, or holes. The ends and/or shoulders may be machined to accommodate bearings, couplings, and the like. It is not designed for use in aligning by fitting into corresponding holes of another item. For items used to support rotating members see axle(1), shouldered. For items not having any of the above conditions see pin, shoulder, headless. Excludes shaft(1), straight; and axle(1), straight.
Classification: Transmission shafts and cranks, except camshafts and crankshafts
NSN 5965-00-242-8039
NSN 5985-01-258-4769
NSN 6135-00-603-4859
NSN 6610-01-022-2474
NSN 6150-00-056-8002
NSN 5950-00-310-4655
NSN 5965-01-283-6106
NSN 6320-00-688-9983
NSN 5895-01-349-6045
NSN 5935-00-440-2673
NSN 6220-00-184-6179
NSN 6645-00-149-1100