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TORQUE WRENCHES - The Basics of Controlled Screw-Tightening

Posted by Andrea & Klaus Heilemann on Mon, Nov 12, 2018 @ 21:11 PM

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Almost all screw connections used in industrial applications today need to be tightened to a specific torque in a controlled manner.

For you to be able to rely on screw connections being secure, knowledge, and a reliable and robust torque tool are essential.


Definition and Function

  • A torque wrench is a hand-held tool that is used to apply a defined torque (turning force) to a screw connection in order to obtain the required clamping force between the components to be connected, even when maximum loading forces are present
  • Owing to the lever principle, it is important that torque wrenches are only used at the handle. Extending or shortening the lever arm will change the torque values
  • Torque is calculated from the physical values "force times distance" in one rotary motion. The equation is force F x lever arm r = torque MATORN_torque_wrenches

M = F x r

  • The tightening torque is the force most often specified in Newton x meters (Nm) that is generated at the end of a lever arm and creates the corresponding pre-tensioning force of a screw connection. The screw tightening torque is made up of the thread tightening torque and the supporting friction torque

Recommended correct procedure(s) for using torque wrenches

  1. Adopt a safe standing position when tightening the screw connection
  2. Relax the torque wrench after use — this will relieve the load on the spring and ensure proper function for a longer period of time
  3. Always release the torque wrench by pulling it
  4. Never use the torque wrench as a hammer
  5. Always select the extension that brings the tool as close as possible to the screw connection
  6. Always keep the torque wrench in the packaging provided to protect it against dirt

Torque_wrenchTaking these steps will go a long way to keep your torque wrench in good working order.


Source for this information are our friends at Hahn+Kolb who produce torque levels with QUALITY ASSURANCE AND GUARANTEE in their ATORN line.


We have prepared the above and more info on ATORN torque wrenches and their characteristics in pdf form as well ...

Download HERE


Topics: General Tools, Worth Knowing, Quality Management, Safety