First collar consists of thread size 3/8in dia, 16 unc-2a thd, 1.875 length
An externally threaded fastener whose threaded portion is of one nominal diameter, and whose unthreaded portion has been machined or ground in one or more places or over its entire length to a maximum diameter less than the minimum pitch diameter of the thread (excludes undercuts for thread relief). It is no. 10 (0.190 in.) (5 mm) or larger in size and has a head which is not designed to be held or driven with an inserted driver or designed for rotation by the thumb and fingers. A locking feature may be incorporated in the design of the head or threads. Excludes bolt, internal wrenching and thumbscrew. See also screw, externally relieved body.
Classification: Other copper screws (not for wood) bolts and nuts
NSN 6145-00-223-2885
NSN 6150-01-503-0658
NSN 5895-00-170-9625
NSN 5999-01-545-0891
NSN 5965-01-161-8097
NSN 6320-01-643-0850
NSN 6150-01-185-5804
NSN 6105-01-091-9985
NSN 6645-01-315-0720
NSN 5935-01-351-4733
NSN 6685-00-656-5057
NSN 5930-01-089-6578