While many of our blog posts focus on torque wrenches, it’s important to recognize some of the other members in the bolt tightening family.

Today we’ll look at one of those tools: hydraulic bolt tensioners.

For this tool to do its job, you’ll need to begin with a bolt that has an end that protrudes above the tightening nut. An annular hydraulic cylinder is then placed around the bolt, applying cold extension. The bolt undergoes an axial traction load, while the nut is turned down with little effort, without transmitting torque to the bolt.

When the tensioner releases its fluid pressure, the majority of the hydraulic load on the tensioner is transferred to the nut and the tightening is complete.

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