Go/no go gauge

Limit gauges ( rare caliber teaching or limit snap gauge ) are teachings that embody the allowable maximum and minimum of a test specimen. Testing with limit gauges whether the actual size of a test object is within the tolerance of a predetermined desired measure. In contrast to the measurements with, for example, a vernier caliper or micrometer no measure is obtained in the form of a numerical value, but it only allows to state whether the test item is true to size and may retain its shape. The great advantage of a boundary theory is that this is cheaper than, say, a three-point internal micrometer, while still very possible to find out whether the machined workpiece "the Committee", "good" or " rework " is.

Similarities of limit gauges

As material comes in limit gauges usually gauge steel used. A test surface carbide is the preferred material because it has a 20-fold resistance to wear. Plastic handles protect the limit gauges before hand heat which would heat the teaching on the standard temperature of 20 ° C and thus the dimensional stability, negatively impacted due to the thermal expansion. With the use of limit gauges is to continue to ensure that the component to be tested should preferably have the same temperature as the limit gauge. When estimating the uncertainty may be roughly assumed 11 microns per m and K.

Have limit gauges on one side of a GO gauge, which can be paired with the test, and at the other end a committee doctrine, which carries a red mark and not be allowed to be paired with the test specimen. The Committee page you can see at a further feature as well; she has a short cylinder, and the upper limit deviation is on this page. Since the GO gauge is always looking flawless test object, it represents a measure and morphology represents the doctrine committee, however, never fit on a proper test object, which is why the shape retention can not be verified. It is purely a measurement gauge.

Taylor shear principle

The Taylor principle (after William Taylor) refers to the design and application of lessons for testing pass parts.

Limit gauges for internal dimensions

To test holes and grooves, using plug gauges. If the surface to be tested flat, flat and special Border teachings are used. The measuring surfaces can be designed in various ways, eg as a cylinder, sphere, hexagon or square, or as thread. The good side represents the minimum and must slide under its own weight into the hole or groove. The Committee may nestle side only. When threaded plug gauge the committee page has two threads and only checks the pitch diameter. According to the standard ISO 1502:1996 ( ISO metric threads of general application ) Kapitel7.1.9 section c may, the Committee page of a thread limit plug gauge maximum of 2 turns can be inserted. The revolutions are counted when unscrewing. The good side has a much longer cylinder than the committee page and is often fitted with carbide inserts. At the ends of the dimension limit is engraved in each case. Commercial plug gauges have in new condition on the good side usually wear oversized, so that the printed value "0" does not coincide with the actual value. For example, a plug gauge 6 H7 has in new condition on the good side a measure of 6.0027 mm, although the tolerance is defined from 6,000 to 6.0129. This wear is excessive but found only on the good side.

Limit gauges for external dimensions

Limit snap gauges and limit gauges, also called teaching mother for external threads, which form the counterpart to limit plug gauges. With them outside dimensions are checked on shafts or threads. Unlike other limit gauges, both sides have a doctrine of the ring gauge embodies only a limit of size. For each study, we therefore need two gauges. The good side embodies the highest level and is thicker than the committee page. Otherwise the same applies as the limit plug gauge.

Thread limit roller snap gauge

The roles of the thread limit roller snap gauge are steigungslos, which right and left threads can be tested in the same manner. The adjustment of the role of distance is set by a thread gages. The rollers are rotatably mounted on axles, in order to reduce the wear of the sensing elements. At each gauging the rollers rotate with the specimen. Wear will be less than that of a thread ring gauge. The front wheels embody the highest level, have the full thread profile and form the good side. The roles of the committee page have only one gear. Fits the specimen through the front wheels, but gets stuck in the underlying committee roles, he meets the requirements. The thread limit roller snap gauge is under the brand name " Aggra " gauge (external thread limit roller snap gauge ) in Europe became known and was especially successful in the 1950s and 1960s. In addition to the low wear was the main advantage of this teaching that workpieces in the machine could be tested without relax them. Thread limit roller snap gauges were replaced in the 1970s by measuring three-role devices.