Multi-jackbolt Tensioner - Basics of Multi-jackbolt Tensioners

Basics of Multi-jackbolt Tensioners

Multi-jackbolt tensioners (MJTs), registered under the trademark Superbolt or Supernut, are designed to decrease the torque required to tighten large bolted joints. One of the major problems associated with traditional bolt tightening methods is as the diameter of the bolt increases, the amount of torque required to tighten it increases in the third power of the diameter. Because of this, the largest size bolt a person can typically tighten by hand is 1". Multi-jackbolt tensioners reduce the amount of torque required to clamp the joint by using multiple jackbolts threaded through the nut or bolt head. The jackbolts, which are small enough to be tightened by simple hand tools, thrust against a hardened washer and generate clamping force on the joint. Loads up to 20,000,000 pounds and greater are attainable using only hand tools. MJTs and related products are produced by Superbolt, Inc. in Carnegie, PA.