Air tools can gage a part for roundness. For two-point out-of-round conditions, a standard two-nozzle air tool can be used. If lobing exists in the part, an odd number of nozzles must be used, depending on the number of lobes.

A common application of Air Gaging is to dynamically measure the straightness or “bow” of an inside or outside diameter. In this case, a custom designed air plug makes verifying a part’s straightness simple and fast. (A straightness air plug cannot be used to measure diameter).

Multiple nozzles are equally located about the circumference of the air tool to allow for average size measurement. Commonly used for thin-walled or out-of-round parts - four, six, or more nozzles are utilizing, depending on the tool size.

The measurement of grooves is conveniently achieved with flat, blade-type air tools. Air Gaging not only determines groove size, but with exploration around the workpiece, parallelism of the groove faces can also be determined.

To determine squareness of a part, for example a bore to a face, air nozzles configured as a “z” are used with dynamic measurement to change the back pressure from square to out of square conditions.

Air Gages are most commonly used for measuring the size and form of inside diameters and outside diameters. Two-nozzle air plugs, with nozzles diametrically opposed, are used for internal measuring, and two-nozzle air rings are used for external dimensions.

Angle variation of tapered surfaces can be checked, with air gaging by comparing the difference of two diameters. The Bowers Air2 (Firmware 1.2 or newer) has DMS (Degree-Minute-Second) capability built in.

A specified clearance between two mating parts is often required to assure proper part operation. The Fowler Bowers Air2 allows for the individual display of the bore size, or shaft size and the clearance between the two parts. Operators need only observe the clearance display to determine if the two components have the required match dimension.