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Getting the best torque control from your wrench

October 15, 2018

Tools Tire changing Impact Wrenches

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.

linkedin expert article - torque regulation

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.

Yann Pasco , Global Business Development Manager – Vehicle Service

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.

BlueTork and FRL Stand (6158120450) in workshop / work on truck wheel
Most pneumatic tools on the market are designed to run optimally on 90 PSI / 6.3 bars. Operators should use an air regulator to gauge the pressure while the tool is connected to the compressor.

A Filter Regulator Lubricator (FRL) limits the air pressure going into the tool and allows regulation of air pressure through the hose. It gives precision to power settings - to adjust the air pressure and achieve better accuracy, mechanics should use a gauge-equipped FRL. If the tool doesn’t receive the air pressure recommended for that tool, then it goes without saying that the tool will not deliver what is expected from its settings.

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.

power regulator - article torque regulation
During the last decade, more attention has been given to the ergonomics and tool’s handling. Most tools were still designed to be operated with one hand, and had clever designs enabling the operator to change the direction of rotation and vary the torque level using a single hand.

Today, focus is being given to delivering the highest levels of precision combined with ergonomics. Tools are being designed to give finer air regulation, and therefore better torque control. Innovation can be found in the newest impact wrenches to help mechanics work more efficiently; for example they don’t need to move the tool to moderate its power as the controlling area is on the back of the tool, with easy access.
impact wrench CP7769 - article torque regulation
Furthermore, specific tools have been developed to prevent overtightening of bolts – for example torque limited impact wrenches. Today’s tools give mechanics better control. The tools have customized settings so the operators can choose how much torque is required.

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.

Yann Pasco , Global Business Development Manager – Vehicle Service

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.

Read more about tire changing

Chicago Pneumatic Experts - what gives power to an impact wrench - how does a pneumatic grinder work

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