Square nuts provide extra wrench-flat surface area and resist rounding, commonly used in older or specialty hardware applications.

Nominal Size: 3/8"
Thread: 16 TPI (Coarse)
Width Across Flats: 5/8"
Height: 21/64"
Material: Steel
Finish: Zinc
Type: Square Nut
A square nut is a four-sided nut. Compared to standard hex nuts, square nuts have a greater surface in contact with the part being fastened, and therefore provide greater resistance to loosening (though also greater resistance to tightening). Square nuts are typically mated with square-headed bolts.