Square nuts can also be used in a channel or welded to other steel products. 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). * They are also much less likely to become rounded-off after repeated loosening/tightening cycles. * quare nuts are typically mated with square-headed bolts. Square nuts are used along with flat washers in order to avoid damage from its sharp edges and helps to increase the strength of the fastener.