Wednesday, November 13, 2013
Differences Between Torque Wrenches
Automotive repairs often require exact settings when tightening fasteners to ensure that parts are properly fastened. The various bolts and fasteners used to assemble an automobile have different tensile strengths, and stresses produced by operation of the vehicle require these fasteners to accommodate these stresses without failing. To place the proper tension on a fastener without exceeding its tensile strength, different types of torque wrenches are used when tightening them.
Digital Torque Wrench
Digital torque wrenches use an electronic display to show the amount of torque applied with the wrench. These wrenches are usually switched between metric measurements and SAE measurements and are also easily set to display torque in either foot pound or inch pound increments. The displays on the wrenches are electrically powered and use either an LCD or LED display screen mounted on the handle to show torque numbers.
Clicker Torque Wrench
Clicker torque wrenches signal when the desired amount of torque is reached by emitting an audible click. These wrenches include a spring inside the handle that places a load on an internal lever. The amount of tension in the spring is adjusted by turning the sleeve on the bottom of the handle to the desired torque level indicated on the handle. When the proper amount of torque is applied, the force applied to the wrench overcomes the spring-loaded lever within the handle, causing it to emit an audible click as it releases. Because these wrenches use a spring to preload an internal lever, you reset them back to zero after each use because prolonged compression of the spring degrades the strength of the spring and reduces the wrenchs accuracy.
Beam Wrench
Beam torque wrenches are the most common type of torque wrench. They have a long pointer beam mounted parallel to the handle shaft. When torque is applied to a bolt, the handle shaft bends but the pointer beam remains straight. The end of the pointer beam then matches up to an indicator mounted to the handle shaft, which shows how much torque is applied. You must observe the indicator on these wrenches from a straight-on view to accurately read the torque readings.
Dial Indicator Torque Wrench
Dial indicator torque wrenches operate similarly to beam-style torque wrenches. Instead of having a separate pointer beam over an indicator mounted on the handle, the beam is enclosed within a housing and moves the indicator on a dial as torque is applied. The dial indicator is easier to read than the indicator on the beam wrench and some dial indicator wrenches include lights or buzzers to indicate when the desired torque setting is reached.
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