Undercut head to accommodate rubber o-ring
An externally threaded fastener whose threaded portion is of one nominal diameter, no 0 (0.060 in./1.5 mm) or larger, designed to be held or driven with either a wrench or an inserted driver or both (excluding internal socket or internal multiple spline types), in sizes below no. 10 (0.190 in./5 mm). No. 10 and larger sizes must have a head designed for any type inserted driver (excluding internal socket or internal multiple spline types), but may also be designed for external wrenching. A locking feature may be incorporated in the design of the head or threads. Excludes bolt, clevis; bolt, externally relieved body; screw, externally relieved body; and screw, assembled washer. See also, screw, instrument; bolt, machine; bolt, internal wrenching; and screw, cap socket head.
NSN 5855-01-538-9436
NSN 6130-01-475-9725
NSN 6110-00-534-1441
NSN 5990-01-432-0523
NSN 6650-01-632-3135
NSN 6620-00-618-1765
NSN 5960-00-177-2953
NSN 6320-01-522-0318
NSN 5960-01-026-9005
NSN 5998-01-300-3830
NSN 6220-01-443-2464
NSN 5965-01-419-6624