Simply put, Torque means “tightening force”. By extension however , torque wrench is a tool that allows you to tighten a fastener to a specific torque value. Basically, exerting too much force on a fastener can lead to damage of the fastener itself or to the parts you intend to fasten. Torque wrench makes sure the required amount of torque is applied and no parts are damaged.
They are mostly used in automotive industries and by auto mechanics to fasten parts together with the least application of stress and right amount of torque. Smaller applications can be handled using spanners of different kinds and not necessarily a torque wrench.
Types of Torque Wrenches
The various wrench types discussed thus are categorized based on their application. However, this category also has numerations that vary by their functionality.
- Click Wrenches :
Click Wrench is the most widely used torque wrench. When the set torque is reached, the wrench produces an audible “click” sound to alert the user. It is useful for sensitive applications that tend to react to over-torque conditions. You can reset this tool to a different torque setting after releasing the pressure.
- Break-Over Wrenches :
Unlike click wrenches, Break-over wrenches deflect about 20 or 90 degrees on torque delivery when the preset torque value has been reached. Therefore, it is very essential for applications that require the limiting of the amount of torque applied to a fastening or an assembly. Technically, it provides a clearer message that the torque value has been reached and then breaks at the torque value. Some Break-over wrenches are automatically reset, while others require manual resetting.
- Cam-Over Wrenches :
Cam-Over Wrenches use a ball and lobe design which allows the tool to slip free when the preset torque value is reached. They are perfect for production applications where over-torque is not condoned as it never exceeds its preset torque value even with continuous application of force on the tool. The influence of the operator is not accounted for in order to produce more accurate results over a wide variety of applications.
Torque Wrench Buyer’s Guide
The various types explained do not exactly give a detailed guide of the things to consider when shopping for a torque wrench. However, while the knowledge cannot be dismissed, some of the equally important things to consider when buying a torque wrench are explained thus ;
Grip: Considering that the typical workplace would be filed with grease and all slippery substances, your grip on any tool is paramount for an effective use. Therefore, an easy grip is a very important consideration.
Visibility of the Scale: For whichever type you end up buying, make sure that the mechanical calibrations or digital display can be read without any trouble especially under stress. The scale must be visible and easy to read.
Material used in manufacture: Obviously, metals are the more durable types. Depending on how long you intend to hold on to your purchase, it is better to go for metal wrenches than cheaper plastic wrenches that may barely handle substantial torque themselves.
Accuracy: Torque wrenches vary in their degree of accuracy. Good wrenches come with a calibration certificate stating the date and accuracy from which you can measure its deterioration and schedule maintenance accordingly.
More on this, if you drop your wrench, there is a probability that the fall has tampered with its accuracy. Therefore, you need to verify when that happens.
Storage: Consider those that come with a hard case (or you can buy one that fits) in order to avoid it being constantly knocked out of calibration.
Warranty: The best torque wrenches have at least one year backing from their manufacturers. You should look out for that too.
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