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 5960-00-197-6282
NSN 5985-01-380-0989
NSN 6320-01-543-3238
NSN 5950-01-298-5875
NSN 6620-00-073-6265
NSN 6105-01-401-5361
NSN 6110-01-521-3865
NSN 5950-01-005-0111
NSN 5920-01-444-4082
NSN 6145-00-147-8515
NSN 5935-00-863-8583
NSN 5920-00-535-1480