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 2925-01-157-9204
NSN 5999-01-325-3916
NSN 6620-00-911-6747
NSN 7035-01-026-1171
NSN 5920-00-166-7877
NSN 5965-01-652-5268
NSN 5985-01-348-6579
NSN 6135-01-100-3593
NSN 6220-00-383-9402
NSN 5975-01-613-7026
NSN 5985-01-206-5827
NSN 6620-01-657-6296