Services: Thread Rolling

Superior strength and resistance to stripping. 

Thread rolling is a process by which steel is extruded to form the threaded portion of a bolt, instead of being removed as in cut threading. In this process, a bolt is manufactured from a reduced diameter round bar. For example, a 1” diameter bolt is manufactured from .912” diameter round bar. This “pitch diameter” material is approximately the midpoint between the major diameter (peaks) and minor diameter (valleys) of the threads. The bolt is “rolled” through a set of threading dies which displaces the steel and forms the threads. The end result is a fastener with a full 1” diameter threaded portion but a reduced body diameter (.912).

The above diagrams indicate rolled threads superior strength and resistance to stripping, up to 30%.  A rolled thread grain structure is not broken in any way.  It is instead, cold worked in unbroken lines that follow the contour of the thread.  Therefore, for a shear failure to take place it must occur across, rather than with the grain.

We offer a wide range of thread sizes up to 1” diameter, we can also do diamond and straight knurling to your specifications