Impact wrenches are essentially socket wrenches converted into power tools.  They provide a high torque with minimal exertion for the user.  The tool offers a hammering action that helps tighten fasteners such as nuts and bolts.  Unlike corded impact Wrenches which run on either air or electricity, cordless impact wrenches are powered through Rechargeable batteries.  These tools are widely used in many industries, including auto repair, heavy equipment maintenance, product assembly, major construction projects, and any instance where high torque is necessary.  Impact wrenches can be used to drive lag bolts, tighten pipe couplings, change tires, and many other fastener driving tasks.  Since they provide the torque of corded impact wrenches with the convenience of cordlessness, these tools are great for places with no power source, or in the outdoors.

Features and working of the cordless impact wrench

The cordless impact wrench works on the principle of converting the impact of multiple mini Hammers within the tool into a rotary motion, generating the requisite torque. The power to generate this motion is provided by the battery. This average torque generated varies from around 300 to 325 ft. lbs. resulting in a speed varying from around 1450 revolutions per minute (rpm) to approximately 2450 rpm. This rpm value generates an effective output of around 2500 to 3000 blows per minute (bpm). This power enables the tool to drive larger holes, drive bigger screws, and also remove heavier nuts.  They are great for removing fasteners that have become rusted or otherwise artificially glued through wear and tear or weather.

The gears are made of a heat treated alloy material to enhance power and durability. The gear case of the impact wrench is made of magnesium for better durability. Some wrenches have a hanger bracket incorporating a steel ring, allowing the tool to be tethered when used overhead. This ring is also useful when using the tool perched on a ladder or a utility pole.

Some of these tools incorporate an impact-resistant, glass filled nylon housing with a unique airflow system for increased performance. The wrench’s cushion mounted motor seeks to further absorb the vibration shocks. One kind of motor having an intrinsic rare earth magnet enhances the power output of impact wrenches by around 20 percent.

A rocker switch design facilitates the quick and easy fixing or fasteners, with easier forward / reverse controlling access. Additionally, a heavy duty impacting system targets the torque to the fastener without any kickback. Some tools have a half inch anvil design offering better durability. Most impact wrenches use a 3/8 inch or a 1/2 inch Square anvil to enhance the impacting functionality.

When using such a powerful tool for extended durations, the vibrations could cause fatigue and joint impact on the operator’s hands. In order to minimize this drawback, the tool is rendered with a soft grip on the handle to offer a slip-free grip and also create a vibration-absorbing facility.

The voltage Level of these wrenches range from 12 volts (like the Makita 6918FDWD to the left) to 14.4 to 28 volts (like the Milwaukee 0799-20 to the right). The greater the voltage, heavier is the performance capability of the tool. The user has the option to control the speed of the tool depending on the application, through the variable speed switch.

Most cordless impact wrenches ship with two batteries, and a charger. Lithium-ion batteries are normally preferred to Ni-Cd batteries for impact wrenches because of their lighter weight and longer lifespan. A reversible battery pack enables better balancing of the tools, especially when it is pointed overhead or when used in relatively inaccessible areas.

The overall length of the cordless impact wrench is approximately one foot, while the weight varies between around six to twelve pounds.

What to look for in a cordless impact wrench

Since this tool is subjected to regular impacting and rough use, its maintenance and servicing is of paramount importance. Externally accessed brushes enable easy servicing. A handle that juts out of the mid portion of the tool enables better balance and maneuverability. During use, it would be a great advantage if various controls of the tool are easily accessible, enhancing single hand use and saving time as well as effort for the operator. The incorporation of a 1/2 inch pin / detent socket retainer helps to retain Sockets and adaptors in a more judicious manner. Some of the popular manufacturers of cordless impact wrenches are Chicago Pneumatic, DeWalt, Makita, and Milwaukee.