2nd step on 1st end splined, largest diameter flatted 2 sides
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 5835-01-045-6371
NSN 4140-00-820-1173
NSN 6320-00-779-5923
NSN 5920-01-208-4981
NSN 5965-01-333-8560
NSN 5999-01-104-8984
NSN 6610-00-800-7645
NSN 5960-00-262-0650
NSN 6240-01-560-0910
NSN 6220-01-101-1912
NSN 5998-01-501-4545
NSN 6320-00-937-5625