Controlled tightening

  1. Where can I get a calibration certificate for torque tools?
  2. How to request a calibration certficate?
  3. Which certificate should be requested to get a warranty assuring both correct tightening and norms?
  4. What is the validity of the calibration certificates and how long does it take to be delivered?
  5. Which is the couple of tightening of a torque tool?
  6. Is it possible to re-calibrate a torque tool? What shall I do?
  7. What is the difference between the transmission ratio and the multiplication ratio?
  8. What are the functions of the torque multipliers?
  • Where can I get a calibration certificate for torque tools?
    The calibration certificate of a torque wrench can be released by the SIT Calibration Centre UA in Monvalle. UA has obtained the prestigious accreditation as SIT Calibration Centre for torque measurements between 9Nm and 1000 Nm, in compliance with the UNI-CEI EN 45000 norms.
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  • How to request a calibration certficate?
    Phone and send a fax ( a written documentation is required) to the SIT Calibration Centre UA and request the SIT certificate or the UA certificate.
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  • Which certificate should be requested to get a warranty assuring both correct tightening and norms?
    • The SIT certificate is requested when the torque wrench is used as “primary tool”, which means for the control of other internal instruments (calibration, precision control..) This kind of certificate is the most complete one and is recognized by the Giovanni Colonnetti Metrology Institute.
    • The UA CERTIFICATE displays less information than the SIT certificate.
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  • What is the validity of the calibration certificates and how long does it take to be delivered?
    • a fixed validity is not supplied because it mostly depends on the use and especially on how often the client uses the wrench.
    • It takes 10 workdays (starting from the day) since the SIT receives the wrench in order to obtain a calibration certificate.
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  • Which is the couple of tightening of a torque tool?
    • COUPLE OF TIGHTENING: conversion factors
     
    Ncm
    Nm
    Kgcm
    Kgm
    in.lbs
    ft.lbs
    Ncm
    1
    0,01
    0,10197
    0,00102
    0,0885
    0,00738
    Nm
    100
    1
    10,197
    0,10197
    8,85
    0,7375
    Kgcm
    9,807
    0,09807
    1
    0,01
    0,868
    0,0723
    Kgm
    980,7
    9,807
    100
    1
    86,8
    7,233
    in.lbs
    11,299
    0,11299
    1,152
    0,01152
    1
    0,0833
    ft.lbs
    135,59
    1,3559
    13,826
    0,13826
    12
    1

    PRE-LOADING AND COUPLES Table [PDF-file - 346Kb]

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  • Is it possible to re-calibrate a torque tool? What shall I do?
    It is possible to have the tool re-calibrated at our SIT centre.
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  • What is the difference between the transmission ratio and the multiplication ratio?
    The transmission ratio is a theoretic value, the multiplication ratio is a real value.
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  • What are the functions of the torque multipliers?
    They have 2 functions:
    • High-torque loosening (e.g. wheel nuts for industrial vehicles). In this case you can employ a ratchet or a sliding tee
    • High-torque tightening. For controlled tightening a torque wrench should preferably be used.
       
    Use the following method to calculate tightening power:
    Input torque= required output torque/3,4 (3,4 multiplication factor)
    For example: If a fastener should be torqued to 340 Nm:340/3,4=100 (100 Nm is the torque value to set on the torque wrench)
    CAREFUL: Do not employ impact tools.
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