Mounting Documentation System for control and monitoring
of the axial, hydraulic bolt-tightening process.


Visualised indication on the display monitor:

  • 100% documented quality of bolt connections
  • Increased work safety thanks to frequent pressure and elongation characteristic monitoring (according to Hooke‘s Law)
  • Automatic shutdown in case of process errors
  • Guarantee of the correct bolting load
  • Ability to prove that the generation of pre-tensioning force was correct in the event of damage thanks to documented logging of the tension positions and pressures and clamping procedure
  • Self-monitoring of the MDS by means of integral self-test and redundant pressure transmitter monitoring
  • Simple, clear and comfortable user interface that leads through process
  • Automated control of multiple pressure circuits in accordance with different pre-tensioning force generation programs
  • Over 60,000 original data sets of tightening parameters can be stored
  • Password-protected parameter input
  • Simple copy and paste of new data sets for new bolting conditions
  • Mobile or fixed units possible
  • Operator guidance in selectable language
  • Long service lifetime and user-friendly maintenance intervals
  • Integral Tool Service Indicator (TSI)
  • Optional Tool Management System (TMS)
  • Ideal for individual or series assembly– rapid pre-tensioning force generation
  • Data output as diagram or table
  • Data output on customer quality assurance sheets
  • Precise pressure generation with a tolerance
  • of ± 10 bar at 4000 bar. More precise pressure range regulation in various pressure ranges according to customer requirements.
  • Almost unlimited capability for archiving of tightening procedures for individual or complete bolt-tightening systems
  • Assembly errors are eliminated due to integrated process guidance
  • High load-cycle values and long lifetime
  • Tensioning programs and reports can be transferred via USB or LAN-Access


Design variants

Wind power industry Engine manufacturing Turbine manufacturing
  • Elongation sensors in various accuracies and measuring ranges
    • Integrated in tool
    • Gauge
    • Gauge with cable
    • Position sensor with magnetic support and cable
    • Clip-on magnetic position sensor
    • Radio-operated position sensor
  • Number of hydraulic outlet ports and pressure ranges
  • Language selection in all languages
  • RFID chip recognition of used equipment
  • Remote control of the MDS
  • Remote maintenance
  • Various power supply voltages

Specification of tightening data (parameters):

  • Excel
  • Input to MDS
  • SAP interface
  • USB interface
  • Copy and paste

Other requirements for pre-tightening generation as well combinations can be represented:

  • Torque and Rotation angle
  • Pre-tightening force
  • Elongation
  • Temperature
  • multiple tightening before, after and during the
    pre-tensioning process

MDS error recognition

The following errors can be identified using MDS, amongst others:

  • Incorrect bolt material
  • Defective bolt material
  • Incorrect flange material
  • Defective flange material
  • Incorrect seal material
  • Defective seal material
  • Too large gaps from pre-assembly
  • Tightening force loss too high due to
    • a: incorrect thread geometry of nut and/or bolt
    • b: excessive surface roughness
    • c: operating error when turning the main nut
    • d: insufficient axial flank clearance
Mobile MDS and other MDS options

Computer-aided bolt pre-tensioning control for on-site use and MDS applications of general engineering applications using manual, air or electrical/hydraulic pressure generators.

Areas of Application

SCHAAF MDS is ideally suited for:

  • Generating a bolt pre-tensioning force for which 100% operational sequencing, safety and data logging are required.
  • Engine-building: Main bearing, connecting rod bearing, cylinder head
  • Power plants: e.g. Turbines, compressors
  • Ring gear bolt connections: e.g. wind power plants
  • Tower fittings: e.g. crane construction
  • General mechanical engineering


Quality Assurance

All MDS are checked for 100 % process security. During order handling, they are accompanied by ongoing quality assurance measures and supplied
with extensive documentation.



SCHAAF MDS are user-friendly, reliable, and manufactured in accordance with the highest level of technical know-how. Our highly-motivated staff would be pleased to train your personnel, in situ or at our works, in the general handling
and operation of the mobile and stationary control unit. In this way, all the process parameters can be entered optimally in order to achieve maximum process monitoring and safety. Of course, the MDS are supplied ready for operation.

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