CP672 Impact Wrenches

Chicago Pneumatic CP672 Series Air Impact Wrenches

The Chicago Pneumatic CP672 series is a family of pistol-grip, trigger-actuated air impact wrenches built around a twin hammer clutch running in an oil bath. The range covers five models and four square drive sizes, from a 3/8 in. wrench producing 350 ft-lb (475 Nm) of maximum torque up to 3/4 in. and 1 in. models rated at 1,290 ft-lb (1,750 Nm). That spread lets maintenance teams, assembly lines, and heavy equipment shops standardize on one tool platform while matching each wrench to the fastener size and torque the job actually requires.

Twin Hammer Clutch Performance

Every CP672 wrench uses a twin hammer impact mechanism, in which two hammers strike the anvil together once per revolution to deliver powerful, balanced blows that seat and break loose fasteners quickly. Running the clutch in an oil bath keeps the mechanism lubricated through continuous use, supporting the durability these wrenches are built for in intensive production and maintenance work.

Choosing the Right Model

Choose a CP672 wrench by fastener size and the torque you need to apply, not by maximum torque alone. Maximum torque describes peak output, which is most relevant when breaking fasteners loose; the recommended working range is the better guide for tightening. As a starting point, the 3/8 in. CP6728-P05R covers lighter-duty fastening, the 1/2 in. CP6738-P05R and CP6748EX-P11R cover the middle of the range, and the 3/4 in. CP6768EX-P18D and 1 in. CP6778EX-P18D handle large bolts on heavy equipment and structural work.

Impact wrenches do not control final torque precisely. Where a joint has a specified torque value, run the fastener down with the impact wrench, then verify or finish it with a calibrated torque wrench.

Air Supply Requirements

The 3/8 in. and 1/2 in. models use a 1/4 in. NPT air inlet, while the 3/4 in. and 1 in. models step up to a 3/8 in. NPT inlet. Air consumption at free speed is about 16 L/s for the 350 ft-lb models and 26 L/s for the 1,290 ft-lb models. For the CP6738-P05R, Chicago Pneumatic specifies a maximum dynamic working pressure of 6.3 bar and a minimum hose diameter of 10 mm (0.38 in.) for a 5 m (16 ft) hose. Undersized hoses, fittings, or compressors are a common reason an impact wrench falls short of its rated torque, so size the air supply to the tool.

Socket Retention

The 3/8 in. and 1/2 in. models hold sockets with a friction ring. The 3/4 in. and 1 in. models use a dual retainer that works with either a friction ring or a hole-and-pin socket, the more secure choice for heavy impact sockets. Always use impact-rated sockets with pneumatic impact wrenches.

Documentation and Support

Operator's manuals, parts breakdowns, and Chicago Pneumatic air impact wrench safety instructions are available for CP672 models. Our team can help you compare models, confirm air supply requirements, and quote the right Chicago Pneumatic impact wrench for your application.