Superbolt tensioners are designed as direct replacements for conventional nuts and bolts. These devices can be threaded onto a new or existing bolt, stud, threaded rod or shaft. The main thread serves to position the tensioner on the bolt or stud against thehardened washer and the loadbearing surface. Once it is positioned, actual tensioning of the bolt or stud is accomplished with simple hand tools by torqueing the jackbolts which encircle the main thread. The jackbolts transfer the preload evenly into the main thread and consequently onto the joint. The main thread is tightened in pure tension.