2nd end has 2 indented flats. There are 2 pairs of flats and a keyway on the center section of the axle
An axle 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), periphersl flat(s), circular groove(s), keyway(s), splines, threads, or holes. The ends and/or sholders 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 transmit motion see shaft(1), shoulder. For items not having any of the above conditions see pin, shoulder, headless. Excludes shaft(1),straight; and axle(1), straight.
NSN 6620-00-556-1976
NSN 5999-01-483-8026
NSN 6320-00-456-2092
NSN 6220-01-566-0976
NSN 6150-01-145-3780
NSN 5990-00-486-0506
NSN 6685-01-400-2925
NSN 6220-01-287-3942
NSN 5910-01-604-1946
NSN 5925-00-892-9932
NSN 5985-00-237-1444
NSN 5998-01-393-4763