Getting the best torque control from your wrench
15 October, 2018
Pneumatic impact wrenches were originally meant for loosening stubborn nuts and bolts. However, nowadays mechanics use impact wrenches for tightening bolts too, for example on wheels, so they can do their job faster, with more efficiency, and increased safety. Here’s some insight on torque regulation and how to make sure the tools are performing as expected.
Good torque control is vital to make sure that bolts are tightened just the right amount (as highlighted in our Torque Sense when Changing Tires blog), and tools are designed with many different options for controlling power levels and torque to satisfy the application.
For example, more power is typically needed for untightening bolts, as they may have become rusted and firmly stuck. However, when tightening bolts, less power is needed. In this case, finer control and care is needed to avoid overtightening, stretching or breaking the bolt.
A tool’s power is dependent on the amount of air in the motor, and there are typically two methods of regulating the power with the air. The first one is by regulating the air pressure, the second is by acting on the air flow directly by either selecting the right air compressor, or by using the correct hose diameter.
Over the years, the design of tools has evolved to enable operators to have better control of the air flow. In the first half of the 20th Century, early, classical models had a lever on the back which was depressed to reduce the air flow inside the tool. These basic impact wrenches employed simple technology that could be used with one hand, but they were never fully precise.
There is no ‘one-size-fits-all’ tool for every garage application, but instead, the best tool for the job depends on the mechanic’s needs, habits and comfort. There is a large choice of impact wrenches available which need to be selected based on several criteria – an important one being how finely you need to control power and torque.
In conclusion, depending where the tool is placed on the air line, close to or far from the compressor, will also have an impact on the air pressure it receives. Therefore, more or less air is needed to arrive in the tool depending on the job and this can be regulated easily by today’s tool thanks to finer precision of operation.
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