GD 8 Nylon Insert Locknuts, National Coarse

Grade 8 Nylon Insert Locknut, NC: Heat treated hex nut with a nylon-filled collar at its back end. The nut shall be grade-marked in one of two ways: (1) with double notched corners or (2) with six symmetrically spaced ientical symbols on the chamfered surface on top of the nut. When the cap-screw or bolt reaches the collar, the threads and nylon form a tight, rictional fit, restricting movement of the cap-screw or bolt when it is subjected to vibration. *ZY - YELLOW ZINC