Abstract: An insert useful for replacing damaged threads in a hole is provided. The damaged threads originally extend along an axial length of the hole. The insert has an inner surface having inner threads corresponding to the damaged threads being replaced. The insert also has an outer surface having outer threads extending an axial length that is greater than the originally extending axial length of the damaged threads. The insert may be used to replace damaged threads in a spark plug hole. A kit including the insert, a tap having a thread milling section, and a retention mechanism implement is also provided. Preferably, the retention mechanism implement is an expansion tool for imbedding knurled threads into surrounding material. The tap has torque engagement mechanism with an outer radial dimension which is substantially equal to or smaller than the maximum outer radial dimension of the tap. An associated method is also provided.

Abstract: Described herein is a nut assembly including a nut and a fastener insert wherein at least one of the components is formed from a nitrogen strengthened stainless steel which is resistant to galling. In addition to reduced galling, fastener inserts formed from the nitrogen strengthened stainless steel exhibits good corrosion resistance and a yield strength which is almost twice that of fastener inserts formed from 304 type stainless steel.