All About Torque
Torque is measured in both length and force. Length refers to the distance from the “center of drive” to the “center of handle.” Force, on the other hand, means “pounds,” “Newtons,” etc. The standard formula is: length x force = torque. When torque is applied to a threaded fastener, it draws the joint together, creating a clamp load as the fastener begins to stretch. Clamp load amount is determined by various factors, including:
- The amount of torque applied to the fastener
- The material and grade of the fastener
- The external friction on the joint
Appling the accurate torque is essential for safety, assembly and performance of equipment. If the inaccurate amount of torque is applied, it can result in loosening or breaking of fasteners and equipment failure.
Types of Torque Wrenches
Electronic Torque Wrench: Electronic torque wrenches, also referred to as digital, are torque multipliers that are connected to an electric motor. These tools are programmable to set limits, by which the torque level is determined. They provide an audible alert once the correct torque is reached and displayed via LED reading. In addition, electronic torque wrenches also include helpful features such as a chip for memory saving, which can be uploaded onto a computer to use for spreadsheets and documents.
Beam Torque Wrenches: The beam torque wrench is the most basic when it comes to this tool. The wrench head and handle are separated by a lever arm. This flexes against a visual indicator (scale) gauge to show the amount of torque weight being applied. These tools are typically heavy in weight and, because they’re manual, are also the most cumbersome in comparison to more developed styles.
Dial Torque Wrenches: A dial torque wrench is engineered to mechanically display the data on a dial. These tools are typically used as a quality control instrument to verify or monitor torque. They can also be used for join testing, auditing or verification of torque applied. This instrument captures the finishing torque applied to a fastener with a memory pointer to provide a high degree of accuracy.
Interchangeable Head Torque Wrenches: These tools fall under the category of click-type torque wrenches. Interchangeable head torque wrenches are extremely versatile, which makes them the preferred choice for various industries like automotive and mechanics. Once the right amount of torque is applied, the tool emits a warning signal or a “click” to prevent over tightening.
Micrometer Torque Wrenches: The micrometer torque wrench has forward and reverse capabilities. It has a quick release trigger so it’s easy to set, adjust and read. It provides fast, accurate tightening fit for metalworking, plumbing and other industrial jobs. Since it’s easily transportable, this tool also has a rubber bumper on the head for protection.
Things to Keep in Mind
Torque wrench use is based on the particular model and type, as well as the task at hand. After all, each style yields different results. Here are a couple of features to take into consideration before buying:
- Material: It’s important that the torque wrench you choose is made up of durable materials that will last through even the toughest of jobs.
- Warranty: All tools should have a warranty, especially if they’re used often, like in a facility.
- Storage: Be sure to consider shelving and storage racks before purchasing each tool. Make sure your workbench has a place for everything.
- Torque wrench calibration: It’s important that your tool is accurate. Getting a torque wrench calibrated by a shop with the proper equipment and technical expertise is a must.
- Grip: It’s important that your tools have all the features needed to make the job more seamless—including an easy grip for safety and precision.
Be sure to put in the necessary research before purchasing a torque wrench to ensure it’s the right fit for you and the task at hand.
The product statements contained herein are intended for informational purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. The information provided herein does not replace the use by you of any manufacturer instructions or technical product manual. W. W. Grainger, Inc. does not guarantee the result of product operation or assume any liability for personal injury or property damage resulting from the user’s reference to any product instructions. This publication is not a substitute for review of the current applicable government regulations and standards specific to your location and business activity, and should not be construed as legal advice or opinion.