Technical Info

Dimensional Gaging Forum: Air Gaging and How It Works

Air gaging is a technology that employs the use of air flow volumes and air pressure to determine the size of measured part dimensions. To achieve this measurement, it relies on the laws of physics, which state that flow and pressure are directly proportionate to clearance and react inversely to each other. As clearance increases, air flow also increases and air pressure decreases proportionately. As clearance decreases, air flow also decreases and air pressure increases accordingly.
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Putting Air Gages to Work

Air gages, past to present, either measure flow or back pressure. Integrated air gaging systems are comprised of these basic components: air regulator, amplifiers, tooling, setting masters, connectors, and accessories. Let's take a look at each type of component and then examine various applications. Learn More

Air Gaging vs. Contact Gaging

Contact gaging measures the dimension from surface roughness peaks of the part being measured (i.e. at plane A - A).

Open nozzle air gaging measures the mean surface of the part, which is approximately the average of surface finish peaks and valleys (i.e. at plane B - B). Technically, the mean surface would be an imaginary plane established by using the material from the peaks to fill the valleys until a level or zero line is formed. Learn More


It is perfectly natural that machinists should have an affinity for mechanical gages. To a machinist, the working of a mechanical gage is both straightforward and pleasing. Air gages, on the other hand, rely on the action of a fluid material, the dynamics of which are hard to (shall we say?) grasp. But air gaging has many advantages over mechanical gages and should be seriously considered as an option for many applications. Learn More

Checking Centrality

1.Calibrate the air gaging system using the max and min masters in a normal manner. Learn More

Checking Nozzle Balance

1. Calibrate the air gaging system using the max and min masters in a normal manner. Learn More


"Air gaging is the greatest thing since sliced bread," a friend once told me.  And he was right — air gaging is good.  It's fast, high resolution, non-contact, self-cleaning and easy to use.  For use in a high-volume shop, it's hard to beat.  But that begs the question, "If air gaging is so good, why would you ever consider going back to contact type gaging?" Learn More