Description:

Size: 5/16 inch-18.
Similar in shape and function to a standard finished hex nut but is about half as thick.
Used as a second nut to "jam" or prevent the main nut from loosening.
Can also be used in place of a standard finished hex nut in cases where a standard nut will not fit.
If using one thin nut and one standard nut, the thinner nut goes in first.
Thread Type: Coarse, Thread Class: UNC-2B.
Specification(s) Met: ASME B1.1 and SAE A563.