Principle of pneumatic gauging for application in process control in quality parameters like measurement of true dimension of holes, tapers, height, width, depth, thickness, centre to centre distance, chamber, straightness, outside diameters, ovality etc. This technique employs compressed air passes through a primary restrictor, before entering the cavity upstream of escape or delivery orifice. The charges in pressures can be calibrated into terms of quality parameter or characteristic of desired, viz. outside diameter of hole or taper.

This paper envisages the design of such pneumatic gauging for the quality characteristics mentioned earlier. The novelty of this technique of is the non- contact type i. e. many time the instrument probe need not be in physical contract with measuring surface or measuring parameter. Thus this technique is amenable for in process control of parameters whose material is of very soft and fragile and sensitive, at a very high accuracy. As the technique is of NDT, cost scrapping very minimal and does not necessitate highly skilled operator for inspection of job. This paper also highlights some of simple techniques for testing of weldments. These NDT ways are employed uses penetrants, vacuum, pneumatic pressures, acoustic emission. Acoustic emission works on "metal cry", can be tested for live cracks as the welding is carried out. Thus this paper presents overview of NDT for testing of weldments and also presents some simple but effective ways inspection in welding.

This paper concludes that the non-destructive tests plays vital role in monitoring the manufacturing and leads way to zero defect manufacture and aims at lowering manufacturing costs by eliminating and reducing costs of rework and scrapping.