Glossary of Gaging Terms
- The readout of an air or electronic gage system.
It displays readings on a scale as dimensional
values. When connected to air or electronic gage
tooling, readings are amplified many times, allowing
the user to easily read the size being measured.
- The resultant non-movement on the display of an
air amplifier that occurs when one nozzle of a
two-nozzle tool is closed toward the workpiece and
the other nozzle equally compensates for that
- An air or electronic amplifier featuring a
vertical bargraph display.
- Refers to air tooling designed to measure
Close-To-Shoulder. As an example, an air plug used
to measure counterbores. Removal of front center
post on air plugs below 2.510" becomes a blind hole
- Full Scale Value (FSV)
- The numeric equivalent of the graduated display.
FSV is usually 1-1/2 to 2 times greater than the
tolerance being measured to show approach or
- The visual increase of size that is created by
an amplifier. In systems where the air amplifier has
adjustable magnification, this is accomplished by
adjusting the flow or back-pressure within the
amplifier to agree with the master sizes. On systems
that have an air amplifier with fixed magnification,
it is essential that the air gage tooling is precise
so that full amplification can be achieved.
- The orifice in the air gage tooling that emits
the air which blows against the part being measured.
The diameter size of the nozzle is dictated by the
air gage system used. The quantity and location of
nozzles are determined by the measurement
- Nozzle Drop
- The engineered distance that a nozzle is
recessed below the surface of the air gage tool.
Nozzle drop is governed by the air gage system. A
deeper nozzle drop can provide longer wear life of
the air gage tool.
- The smallest increment on the full scale display
of the amplifier. For example, the Edmunds air and
electronic columns have a full scale with 100
graduations. Therefore, the resolution is 1/100th of
the full scale value. Restriction - A device used to
control air pressure or flow within an air gage
amplifier. This may be done with a fixed orifice of
a precise size, with adjustable needle valves, or
- The process of positioning the magnified spread
on an amplifier to a desired relative position on
the scale. Zero is generally at midpoint of the full
scale, but the spread may be positioned anywhere on
- Zero Size
- The desired midpoint or nominal size of the
feature being measured as it relates to the scale.
On back-pressure systems, zero is usually the
midpoint between the minimum and maximum allowable
size. On the flow system, the zero size is generally
the minimum size.