NO GO ring gauges. The NO GO gauges
distinguished by an annular groove cut in the knurled
outer surface of the ring.
Tolerances. Depending on the use, ring gauges
are manufactured to different tolerances. The following
classes of gauges and their limits of accuracy are
standard for all makes:
Precision lapped to close tolerances
for many types of masters and the
Good lapped finish to slightly
Commercial finish (ground and
polished, but not fully lapped) with
fairly wide tolerances.
Class ZZ- Ground only to meet the demand for
an inexpensive gauge, with liberal
Tolerances for ring gauges in each class are listed in
Use. Ring gauges are used more often in the
inspection of finished parts than parts in process. The
reason for this is that the finished parts are usually
readily accessible; whereas, parts in a machine that are
supported at both ends would have to be removed to be
checked. A part such as a pivot stud is checked by
performing the following procedures (see figure 3-58):
Line the stud up with the hole in the GO
gauge, and gently press it in. If the stud will not go in,
the shank is too large. If it will go in, the stud is not
With the stud in the hole, check the piece
for taper and out-of-roundness by gently shaking it and
sensing any wobble.
After checking the part in the GO gauge,
check it in the NO GO gauge. If the stud is within
desired limits, it will not go into the gauge.
maximum dimension of a part and NO
GO plug gauges control the minimum
dimension of a hole. Therefore, GO
gauges control the tightness of fit of
mating parts and NO GO gauges control
the looseness of fit of mating parts.
Table 3-1. Ring Gauge Tolerances
3 Ground or polished (grinding marks may be in evidence)