TM 9-243
TYPES AND USES
RING GAGES
The plain ring gage is an external gage of circular form.
For sizes between 0.059 and 0.510 inch, ring gages are
made with a hardened bushing pressed into a soft body.
The thickness of the gage will range from 3/16 to 1-5/16
inches. On ring gages, the GO gage (1) is larger than
the NO GO gage (2). The GO and NO GO ring gages
are separate units. They can be distinguished from
each other by an annular groove (3) cut in the knurled
outer surface of the NO GO gage. Ring gages made for
diameters of 0.510 to 1.510 inches are the same as
those shown above, except there is no bushing; they are
made all in one piece. Ring gages, sized from 1.510 to
5.510 inches are made with a flange (4). This design
reduces the weight, making the larger sizes easier to
handle.
Ring gages 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.
SNAP GAGES
The plain snap gage is made in two general types, the
nonadjustable and adjustable. The nonadjustable type
is a solid construction, having two gaging members, GO
(1) and NO GO (2) as shown above. The part to be
inspected is first tried on the GO side and then the gage
is reversed and the part tried on the NO GO side. Some
solid snap gages (3) have combined gaging members in
the same set of jaws as shown above, known as a
progressive snap gage. The outer member (4) gages
the GO dimension and the inner member (5) the NO GO
dimension.
Three standard designs of the adjustable type are
available, consisting of a light, rigid frame with
adjustable gaging pins, buttons, or anvils. These pins or
buttons may be securely locked in place after
adjustment, and locking screws are tightened to hold the
gaging dimensions.
One type of adjustable snap gage is made in sizes that
range from 1/2 to 12 inches (1). It is equipped with four
gaging pins and is suitable for checking the dimension
between surfaces. Another type is made in sizes that
range from 1/2 to 11-1/4 inches (2). It is equipped with
four gaging buttons and is suitable for checking flat or
cylindrical work.
The third type is made in sizes from 1/2 to 11-5/8 inches
(3). It is equipped with two gaging buttons and a single
block anvil, and is especially suitable for checking the
diameters of shafts, pins, studs, and hubs.
15-3
