Care. Observe the following practices for the
care and upkeep of ring gauges:
Always make certain that the surfaces of
the parts gauged and the gauge itself are kept free from
abrasives, dirt, grit, chips, and all foreign matter.
Always consider the abrasive action of
the part on the gauge. Cast iron, steel, and cast aluminum
are more abrasive than brass, bronze, and nonmetals such
as plastics. Use particular care when gauging cast iron,
steel, and cast aluminum.
When gauges are stored, arrange them
neatly in a drawer or case so that they do not contact other
tools or each other.
Always hold the gauges in your hands
when checking. Never clamp them in a vise.
At frequent intervals, check all gauges
for accuracy and wear with gauge blocks or master gauges.
3-16. Snap Gauges. Snap gauges, shown in figure 3-59,
are used as standards to determine whether or not one or
more dimensions of a manufactured post are within
Description. The snap gauge is made in two
general types, the nonadjustable and the adjustable.
Nonadjustable. The nonadjustable type
is a solid construction, having two gauging members, GO
and NO GO, as shown in figure 3-60. The part to be
inspected is first tried on the GO side and then the gauge is
reversed and the part is tried on the NO GO side. Some
solid snap gauges, shown in figure 3-61, have combined
gauging members in the same set of jaws as shown above,
known as a progressive snap gauge. The outer member
gauges the GO dimension, and the inner member the NO
Adjustable. Three standard designs of
the adjustable type are available, consisting of a light, rigid
frame with adjustable gauging pins, buttons, or anvils.
These pins or buttons may be securely locked in place
after adjustment, and locking screws are tightened to hold
the gauging dimensions.
First type. One type of adjustable
snap gauge is made in sizes that range from 1/2 to 12
inches. It is equipped with four gauging pins and is suitable
for checking the dimension between surfaces. It is shown
in figure 3-62.
Figure 3-59. Snap Gauges
Figure 3-60. Solid Nonadjustable Snap Gauge