Multiple Stud Nut
Function of a Multiple Stud Tensioning (MSN) PG 48 in simplified representation

After the pretensioning force generation, the MSN stays on the bolted respectively component connection. Due to mounting without further accessories, the MSN is an economic and effective axial bolt tensioner with little diffusion.

Basic position
The MSN is screwed onto the bolt being tightened until lying at the clamping disc. The Jackbolts are integrated into the nut body and ready for pretensioning generation..

Elongation and compression
Due to the stepwise turning of the
Jackbolts with torque, the
axial pretensioning force is
generated. The bolt being tightened
is elongated and by leading in the
force into the disc the flange parts
are compressed.

After reaching the required torque, the pretensioning force of the bolt is achieved. The sum of the axial pressure forces of the Jackbolts is in accordance with the overall bolt pretensioning force (axial traction). The main bolt is pretensioned absolutely torsion-free. The Multiple Stud Nut automatically is protected against loosening.




The SCHAAF MSN – Multiple Stud Nuts offer you many advantages compared to conventional fixing devices and methods of mounting:

  • Main bolt is pretightened 100 % torsion-free
  • No torsion under load (no thread wear)
  • Robust, durable and lightweight mode of construction
  • Simple and easy mounting and dismantling
  • Permanent maintenance-free connection
  • Wide choice of sizes and designs
  • Anytime quickest control possibility of the
    pretensioning force
  • Mounting with many individuals possible
  • Easy pretensioning control
  • Tensioning locking at static, alternating and impact loads
  • Improves the bolt lifetime because of gentle
    pretensioning force generation and pure axial load


The SCHAAF MSN – Multiple Stud Nuts can be manufactured/supplied as follows:

  • Compact design
  • Standard design
  • High-tensile design
  • Customer specific solutions up to Ø 1800 mm
  • All sorts of threads, standards and others
    Power transmission elements as e. g. bayonet

  • Materials
  • High-tensile steel
  • Rust and acid-resistant steels
  • Heat-resisting materials
  • High-strength aluminium alloys
  • Different material combinations

  • Surface finish
  • Burnished, lacquered or chemically nickel-plated
  • Requested by the customer

User-defined special designs possible.


Fields of Application
  • General mechanical engineering
  • Metal industry
  • Structural and civil engineering
  • Refineries, chemical industry
  • Powerplant technology
  • Research technology
  • Onshore / Offshore


Quality Assurance

All MSN – Multiple Stud Nuts are checked for material quality, dimensional accuracy, proper operation and reliability. They are subject to quality assurance measures during order execution and delivered with detailed documentation.


MSN are, of course, delivered packaged ready for installation and operation.

SCHAAF MSN are user-friendly, reliable and are manufactured in accordance with the highest level of technical know-how. Our highly-motivated staff will be pleased to train your personnel, in situ or at our works, in the general handling of MSN.