Patent for a new and improved nut lock. This design consists in "[t]he combination of the bolt, the nut having a dovetailed groove across its face, of uniform width throughout its length, and a recess at one side of said groove, and a key having tapered sides and sliding into the dovetailed groove from one side of the nut, said key having a pointed end to engage the bolt and also provided with a projecting part to be bent over into engagement with the recess in the nut" (lines 69-78).