Types of Limit Gauges

The various types of limit gauges used for gauging internal diameters of holes are:

1)    Full form cylindrical plug gauge: The gauging surface is in the form of an external cylinder. Generally a small circumferential groove is cut near the leading end of the gauge and the remaining short cylindrical surface is slightly reduced in order to act as a pilot.

2)   Full form spherical plug or disc gauge: The gauging surface is in the form of a sphere from which two equal segments are cut off by planes normal to the axis of the handle.

3)   Segmental cylindrical bar gauge: The gauging surface is in one of the two forms: one form; external cylindrical form from which two axial segments are made by lowering down surface at other places.   the other form;  external cylindrical  form  in which  segments are formed by removing remaining material.

4)   Segmental spherical plug gauge: It is similar to full form spherical plug gauge but has two    equal segments cut off by planes parallel to the axis of the handle in addition to the segments cut

off by planes normal to the axis of the handle.

5)   Segmental cylindrical bar gauge with  reduced  measuring  faces: It is similar to  the segmental cylindrical bar gauge but has reduced measuring faces in a plane parallel to the axis of the handle.

6)   Rod gauge with spherical ends: It has spherical end surfaces which form part of one single sphere.