Tension Rods

Spherically seated tension rods are used with universal testing machines in order to mount external tensile accessories to the load frame. Typically, spherically seated tension rods are used as a matched pair of assemblies. Assemblies for a semi-open or a closed crosshead designs consist of a stud, an adapter plate, a hex nut, a cover plate, a recoil washer, and a jam nut.

Principle Of Operation

Spherically seated tension rods are engineered to provide an ideal mounting platform for external tensile fixtures. They allow for easy changing of accessories and also provide simple and precise alignment through an adapter plate that is bolted into the crosshead. This adapter plate holds a spherical bearing to seat the threaded alignment rod. 

Engineered to be compatible with a wide range of frames, the assemblies can also be used with a variety of accessories, including T-Grip Jaw holders, Threaded End Specimen Holders, Shoulder End Specimen Holders, and Fastener Testing Bolt Holders. These accessories are mounted onto the threaded portion of the spherically seated tension rods, and provide the interface between the machine and the specimen. 

Because the threaded alignment rod is engineered to seat into the spherical bearing of the adapter plate, alignment of the specimen load train is automatically achieved when tension is applied. This design feature ensures axial loading of the specimen.

Application Range

  • The ideal accessory for mounting external tensile fixtures to an existing frame 
  • Spherical bearing provides simple and precise alignment of load train 
  • Design allows for quick and easy changing of accessories 
  • Operate in static tension only


Item Name Capacity Compatible Frame Models Cat #
Tension Rods - 1,780 kN, 400HVL 1,780 kN 400000 lbf 5596, 400HVL W-5131-X