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 6620-00-170-5296
NSN 6240-01-311-1121
NSN 6110-01-421-2714
NSN 5930-00-931-1195
NSN 6240-00-319-4549
NSN 5996-01-529-0639
NSN 6685-00-562-5394
NSN 6110-01-025-9773
NSN 5835-01-325-5677
NSN 5999-00-807-8104
NSN 5999-01-415-5090
NSN 5905-01-018-8922