There is a dizzying array of wrenches, ratchets, torque wrenches and other tools designed to install and tighten a wide range of bolts and fasteners. This can be a little confusing if you are unfamiliar with the terminology and are looking to buy the right tool at the local hardware store. Torque wrenches are a type of wrench commonly used in automotive work and other tasks where a precise torque setting is needed for a specific bolt. Ratchet wrenches are more simple wrenches designed for loosening and tightening bolts.
A torque wrench is a wrench that has a torque reading gauge incorporated into its design. The torque is read by the user in two different ways, depending on the type of torque wrench. The most common and less expensive type has a torque scale printed on the end of the wrench. As the wrench is turned on a bolt, a pointer tells the user how much torque is being applied to the bolt. There are also digital torque wrenches, which utilize a digital display that gives the torque reading. Depending on the type of torque wrench, measurements will be in ounce-inches, pound-inches or pound-feet.
A socket set is needed to utilize a torque wrench. The needed socket is placed on the end of the torque wrench. The socket is then used to fully tighten the bolt or fastener. Torque wrenches are commonly used on automobiles to precisely tighten bolts and fasteners to the manufacturer's recommendations. Torque wrenches can be used on any bolt that needs to be tightened to a specific setting. Because torque wrenches do not have a ratcheting mechanism, a ratchet is usually used to tighten the bolt. The torque wrench is then used to apply the final torque setting.
Ratchet wrenches look similar to a standard open-ended or box-end wrench. However, ratchet wrenches feature a ratcheting mechanism in the end of the wrench that allows the wrench to tighten or loosen a bolt without removing the wrench from the fastener. With a normal wrench, the user turns the bolt, removes it from the bolt and repositions it so it can be turned again. The ratchet wrench allows for quick loosening and tightening of bolts. The direction of the wrench (loosen or tighten) is controlled by a small lever. Ratchet wrenches should not be mistaken for a ratchet, which is a ratcheting handle that a socket is placed on.
Ratchet wrenches can be used on any bolt or fastener that needs to be quickly and efficiently removed. Most hardware stores and auto parts stores sell ratchet wrenches in sets which can used for household, automotive or other projects.