Hydraulic nuts enable large diameter bolts to be tensioned with ease to high and accurate preloads. A hydraulic pump activates the internal jacking system, so the effort required to tighten a very large diameter bolt is reduced to the effort needed to operate the pump.
As there is no nut rotation during tightening, the operation can be performed in a confined space and torsional stresses on thread damage are eliminated. Any number of hydraulic nuts can be connected together for simultaneous operation, ensuring all bolts in the joint can be evenly loaded to the same high and accurate preload.
Available as bottom collar, top collar and shim type
Standard 1500bar and 2500bar designs
Substitute’s original nut – combines tensioner and permanent nut
All in one solution – nut remains in place post tensioning
Special designs available
Supplied up to M400 in size (to date) – larger sizes quoted
High temperature solutions available
Quick and easy to install
Even and accurate load as it is developed hydraulically
Low loss of initial load (shim)
No torque or torsion stress
No flogging hammers or spanners
Improved fatigue performance
100% simultaneous tension
Long life of internal jack – very compact and cost effective
Less stud protrusion required than for tensioners
Testing & Certifications
Boltight is LRQA certified for quality and environmental assurance to ISO 9001: 2015. All tools are assembled, filled with oil and pressure tested prior to dispatch.