Air Probes – Western Gage Corporation

Air Probes for Internal Diameters

The air probe (also referred to as an air plug gage, air spindle or mandrel) consists of a precision ground hardened steel body incorporating two or more air gage nozzles. Air is passed through the probe body to the nozzles where a back pressure is produced by the surface of the workpiece. An air gage readout (air comparator) senses the resulting back pressure and displays the size of the workpiece.

As shown in the drawing, the nozzle tips are recessed a small amount below the body of the probe. This feature makes the air gage non-contact and more wear resistant. The air flow also helps clear contaminants.

Through the use of the opposed set of nozzles, the measurement is made independent of how the operator positions the probe radially within the test bore. This “differential” type of measurement makes it possible to obtain highly accurate measurements with limited operator skill.

Standard Air Probes

Air Probe Thru-Hole

Thru-hole Style Air Probes have the
sensing nozzles set back from the end,
which provides maximum wear life.

Air Probe Blind

Blind Style Air Probes have the sensing nozzles near the front
end, allowing you to gage to the very end of the bore or part.
Super Blind Probes have jets even closer to the front end.

Dimensional Air Gage Options

Miniature Air Probes

Miniature Air Probes as small as .059”
Diameter for tight tolerance holes
available in dual master systems only.

Extended Length Probes

Extended Length Probes in lengths
up to 4+ feet are available for
measuring long tubes or deep bores.

Probes with Stop Collars

Probes with Stop Collars precisely
adjust to the exact datum point
where your part needs to be measured.

Air Probes with Handles

Tubular handles are standard on large Series 60 to
80 Air Probes (Single Master) above 2.510”. Handles
for light, medium and heavy duty applications are available.