Bolt Tensioning Solutions

Whatever Comes Along We Hold It Together

Having developed a deep understanding of bolt tensioning, Nord-Lock can offer a choice of mechanical or hydraulic bolt tensioning for your application in industries including oil & gas, mining, power generation, wind and heavy industry.

Superbolt revolutionised the world of nuts and bolts with the multi-jackbolt tensioner (MJT) and since then has proven its technology with multiple successful installations.

Boltight hydraulic bolt tensioners are used extensively across many industries and projects where bolt load accuracy is critical.

Whatever The Task, We Have The Right Tool For Any Challenge

Mechanical Tensioning

Superbolt tensioners are designed as direct replacements for conventional nuts and bolts to 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 the hardened washer and the load-bearing surface.

Once it is positioned, tensioning is accomplished with simple hand tools by torqueing the jackbolts which encircle the main thread.

Hydraulic Tensioning

When tightening a bolt by any method, the operator is aiming to achieve the correct bolt load. Due to friction, this can be challenging to accurately control when using traditional torque tightening methods.

Using determined pressures, our bolt tensioners axially stretch the bolt. The nut is then rotated down the joint face, accurately locking in the bolt load.

Mechanical Tensioning

Tighten with Simple Hand Tools

Superbolt mechanical multi-jackbolt tensioners (MJTs) are an innovative way to tighten large bolts safely and accurately with the use of simple hand tools. Actual tensioning is achieved by tightening the jackbolts that encircle the nut body. Superbolt tensioners are designed as a direct replacement for conventional nuts and bolts. There is low risk of galling, even in space-restricted areas.

Tightening the jackbolts generates a strong thrust (axial) force directed against a hardened washer. Jackbolts have a small friction diameter and can create a high thrust force with relatively little torque input.

Loads are transferred through the nut body positioned on the main thread by hand.

A hardened washer is used to transfer the force while protecting the flange face.

The thrust (axial) force of jackbolts and the opposite reaction force from the main bolt head create a strong clamping force on the flange.

The thrust (axial) force from the jackbolt creates an equally strong reaction force in the main bolt.

Superbolt® Multi-Jackbolt Tensioners

Ensure precise preload and enhanced safety by upgrading existing bolts with Superbolt multi-jackbolt tensioners.

The Superbolt Technology

Bolting Made Simple

Superbolt was the world’s first to revolutionize nuts and bolts with the multi-jackbolt tensioner (MJT) in 1984. Since then, Superbolt has proven its technology in tens of thousands of successful installations.

Superbolt MJTs are easy to work with and provide an overwhelming mechanical advantage with their unique design, which divides the load among multiple small jackbolts. Once installed properly, MJT connections are reliable, and can stay tight indefinitely. Even MJTs of enormous sizes are safe and can be installed or removed by a single worker with ordinary hand tools.

Superbolt multi-jackbolt tensioners take high preload requirements and break them down into manageable torques using the jackbolts threaded through the nut body. They remain easy to install, even on larger sizes, compared to standard hex bolts.

Superbolt tensioners offer you simple and cost-effective tightening of large size bolts. Your joints can be tightened with high accuracy without requiring specialized skills or heavy tooling. A wide range of tensioners is available in the standard series, as well as an unlimited capacity to create special designs to meet your unique needs.

Hydraulic Tensioning

Tighten Single Bolts Or Multiple Bolts Simultaneously

Boltight hydraulic bolt tensioners are high quality tools especially useful for tightening flanges or other critical bolted connections. Multiple tensioners can be used to deliver an even and accurate pre-load. A wide range of products are available for all market segments and custom products can be designed and manufactured to the client’s exact specification.

Hydraulic oil flows into load cell.

Load generated by hydraulic load cell is tranferred into the puller.

Puller transfers the load directly into the bolt.

The nut lifts clear of the flange surface due to the stretch of the bolt and joint compression.

The socket is used to turn the nut down to the joint face.

The axial load retained in the bolt ensures the correct clamping force is achieved.

Boltight Hydraulic Tensioning

Hydraulic tensioning that combines speed and accuracy for your preload requirements. With Boltight®, multiple tensioners operate in unison, resulting in faster operations while ensuring even preload.

Boltight Service & Support

Our products are being strategically stocked across the globe to offer our customers a seamless and fast experience. Receive direct support to optimize your delivery to suit your production timelines. Expect unmatched lead time on off-the-shelf products and customized solutions, anywhere in the world.

Advantages of Hydraulic Tensioners

A hydraulic bolt tensioning tool provides a quick, easy and safe method for tightening large diameter bolts to high and accurate preloads. It does not use torque or require forceful turning of the nut or bolt, like impact wrenches, flogging spanners or hydraulic torque wrenches, where friction is a common enemy.

A hydraulic bolt tensioner is an annular jack, which fits over the bolt and nut to be tightened. The jack pushes against the bolted joint and pulls on the end of the bolt. Because the force produced by the jack is applied directly to the end of the bolt, a tension equal to the load generated by the jack is developed in the shank of the bolt. With the jack applying tension, it is possible to rotate the nut with zero torque until it is tight. The load applied by the jack is then relaxed and a high percentage, depending on the length of the bolt and its diameter, is retained in the shank of the bolt.

Hydraulic Bolt Tensioning Provides:

Accuracy: Very high bolt load tolerance accuracies, often 5% or better. No frictional losses to consider nor need for lubrication. Easy to calculate load transfer and to prevent overload.
Speed: The tools are remarkably fast to install and operate.
Simultaneous tensioning: Multiple bolt tensioners can be hydraulically actuated at the same time.
Uniformity: Tensioning several bolts at the same time guarantees the same applied load to each bolt.
Safety: No pinch points or reaction issues. The safety engineered into Boltight systems surpasses the industry safeguards.
Versatility: Using adaptor kits, one tensioning kit can often be used to cover a large variety of bolting sizes.
Cost efficiency: Combining the factors above, hydraulic bolt tensioning provides operational value for the customer.