What is indirect gaging and how is a ring gage involved? The process of indirect gaging involves using a ring gage as a reference point against which to set other measuring tools or instruments. Because the ring gage itself is not being used to test the final part, but rather to set another tool which will test the final part, this process is indirect. In essence, two tools are used in conjunction in order to assess the acceptableness of the part being measured. When conducting indirect gaging, the ring gage is known as the master ring or the setting ring. The unique feature of a setting ring is that it is built with a bilateral tolerance. A bilateral tolerance is defined as one half of the specified tolerance added and subtracted from the designated size. This measurement ought not to deviate any more than 0.00001in from the ring gage nominal size.