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 6650-01-419-0286
NSN 6610-00-100-1195
NSN 5910-00-969-2460
NSN 5905-01-162-2968
NSN 6610-00-578-6790
NSN 5905-01-521-2968
NSN 5930-01-629-9486
NSN 5895-01-307-2789
NSN 5990-01-541-5632
NSN 5975-01-559-8731
NSN 6135-00-182-7008
NSN 5935-00-393-3720