1st hub has 2 slots 180 degrees apart
A gear, cylindrical in form, with teeth on the outer surface at an angle to the axis of the gear. See also gear, antibacklash, helical:
Classification: Gears and gearing, other than toothed wheels, chain sprockets and other transmission elements entered separately
NSN 6620-01-542-0494
NSN 6240-01-186-3273
NSN 6220-00-126-2691
NSN 5960-01-142-1995
NSN 5835-01-005-8564
NSN 4140-01-444-1033
NSN 5915-01-388-8339
NSN 6645-00-780-5260
NSN 5960-01-175-9880
NSN 5895-01-175-2670
NSN 4140-01-468-0476
NSN 6220-01-020-8018