Types and Uses

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 com- bined 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 avail- able, 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 dimen- sions. 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