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Air Setup

A short guide to setting up pneumatic tools with an air compressor and air lines.


PSI: pounds per square inch

CFM: cubic feet per minute

Selecting an air compressor

Selecting an air compressor is not as difficult as it might seem. The basic minimum requirement for a small shop a with just a few bays and continual users is a 5 horsepower 80-gallon compressor. Make sure you know your compressor's rated output for CFM and PSI, and make sure these ratings meet the CFM and PSI required by your tools. We recommend the installation of water separators and in line oilers, and as well as a pipe slope with blow-off valves to allow moisture inside the lines to drain out.

Mainting optimal PSI

Most automotive pneumatic tools are rated to operate normally at 90 PSI, and pulling the trigger on most 1/2" impact wrenches drops the pressure by 20 PSI. This means that the pressure set on the air compressor will not match the pressure at the end of the air lines. The length of the air lines, number of tools running, small leaks, and the regeneration point set on the air compressor are all factors in maintaining an optimal PSI for a given tool. A simple PSI tester can be constructed with a few pieces of pipe, a guage, and some connectors, all of which are available at most hardware stores.

Common causes of air restrictions on air supply lines

The air supply hose is too long.

The inside diameter (i.d.) of the hose is too small.

The air connections or fittings have an inside diamater (i.d.) that is too small.

There are too many air connections or fittings being used.

An inline filter is too small or plugged.

An inline regulator is too small, not properly adjusted, or defective.

The air supply hose, air fitting, air tool inlet, or air tool exhaust is plugged.

The pneumatic tool's speed regulator is closed.

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