Abstract: A split nut assembly for mounting on a threaded stud or shaft without passing over the end of the stud or shaft. The assembly consists of a nut divided into two equal parts and a shell equally divided. The shell when assembled fits over the nut so that the assembly can be rotated and tightened together. In a separate embodiment, lock nut capability is provided by providing tapered surfaces on the shell and the nut to force the latter radially against the stud or shaft while the assembly is tightened in place. In another embodiment, a press fit arrangement is provided.