Threaded rod

Undercut studs have a shank equal to the pitch diameter of the screw thread.

Mass-produced fasteners (standard bolts and studs) are usually rolled, but jobbed parts with custom features and small lot sizes are likely to be cut.

The allowable tensile force for a non-undercut threaded rod is defined by the American Institute of Steel Construction (AISC) as[8] where d is the nominal diameter, and Fu is the ultimate tensile strength of the material.

For undercut threaded rods the allowable tensile stress is defined as[8] where ds is the diameter of the shank, and Fy is the yield strength of the material.

Metric threaded rods are marked on the end with a color code to define the ISO strength class.