Not all torque wrenches are alike. When selecting a torque wrench or operating a wrench, it’s important to understand the functions of the tool being used for the fastening application. Take time to read all instructions provided to fully understand the working features and manufacturer recommendations.
The design of certain wrenches, make the tool “length dependent”. What does that mean? It means that the actual torque applied to the fastener varies if the hand position on the wrench is varied (even if the wrench is preset). This occurs if the pivot point of the wrench mechanism is not coincidental with the center of rotation of the fastener or bolt.
Therefore if an operator is holding a “length dependent” torque wrench at the end of the handle, the torque output might be 25 foot-pounds applied for the fastening application. If the operator then changes his or her grip position and holds the wrench at the middle location of the handle, the torque output might be 50 foot-pounds applied for the fastening application.
What is Torque?
Torque is a “turning” or “twisting” force and differs from tension, which is created by a straight pull. However, we use torque to create a tension.
How?
As the nut and bolt are tightened, the two plates are clamped together. The thread angle in the bolt converts the force applied into tension (or stretch) in the bolt shank. The amount of the tension created in the bolt is critical.
Why?
A bolt tensioned properly works at its optimum efficiency and will resist coming undone. However, if the tension is too low, the nut could vibrate or work loose. If the tension is too high (overstretched), the bolt could break. Every bolt has a correct optimum torque/tension figure for each fastening application. It is important to have these figures available so that the end product will be safe, efficient and economical.
How is Torque Measured?
Torque is the result of multiplying the value of Force applied by the Distance from the point of application.
Not all torque wrenches are “length dependent.” Click wrenches, break-over wrenches and other wrench types are commonly a length dependent tool. However there a few click wrenched that are “non-length dependent”, like the Mountz DM-Series click wrench.
Most quality cam-over torque wrenches are a “non-length dependent” tool. Built with a cam-over design, these accurate torque wrenches prevent a fastener or bolt from being under and over tightened. As quality control tool, the Mountz cam-over wrench allows any user to deliver the correct torque with confidence regardless of task and operator skill level.
Before using a torque wrench, make sure you are educated about the correct function of the tool and how to properly use it. Simply picking up the wrench and tightening a fastener until it’s good and tight may not deliver a quality result.
Using a quality torque wrench makes a safer world through accuracy and precision. Controlling torque is essential for companies to ensure their product’s quality, safety and reliability isn’t compromised. The failure of a three-cent fastener that isn’t properly tightened can lead to catastrophic or latent failures. Fasteners that are insufficiently fastened can vibrate loose and excessive torque can strip threaded fasteners.
Need assistance with a fastening application, request an appointment for a torque tool demonstration by a Mountz representative.
