An air chisel resembles a smaller, handheld version of a jackhammer in many ways. This is a pneumatic tool that harnesses the power of compressed air to make the job of chiseling easier. Air chisels are potentially dangerous. Always wear safety glasses and protective clothing when working with one. The high speed that the tool operates at can fling sparks or debris, which can cause injury without the proper protective gear.
Air chisels rely upon pressurized air to provide the force that drives the machine's motion. This force is provided by an air compressor. The compressor uses the motion of a piston to compress air into a pressurized storage tank. An air hose connects the tank to the air chisel then releases air through a regulator to drive the tool.
The air that powers an air chisel is not discussed in terms of pressure alone. Flow is the most important measurement when it comes to this type of power. The air flows down the hose from the compressed air tank, and it is the movement of that air that powers the tool. An air chisel requires between 5 and 11 cubic feet per minute (CFM) of airflow to power the blade. This assumes an average air pressure of 90 pounds per square inch (PSI).
An air chisel is a type of percussion tool. Basically, the high speed air slams into a cylinder and drives the piston forward. The piston, in turn, transfers its force to the head of the tool, which makes the chisel bang forward in a sharp motion. Air also gathers in a return chamber during the down-stroke. That accumulated pressure is used to return the piston to the top of the cylinder.
Air chisels can be equipped with a variety of different heads used for many different tasks. There are scraping chisels, chisels designed to chip away at stone or metal and attachments that turn the tool into a hammer instead of a chisel. These ends can be used to drive nails, for example. Specific cutting ends designed to complete very specific tasks, such as cutting a tail pipe, are also available.