An investigation into the accuracy of industrial measurements as practised by the engineering industries in the Teesside area

Abstract

October, 1966 was the starting date of "Quality and Reliability Year" for British Industry. The author believes that, after the design stage, the greatest contribution to quality and reliability lies in being able to maintain close dimensional control during the manufacturing process. This investigation was carried out with the intention of providing the engineering industries in the Teesside area with a realistic picture of the accuracy of engineering measurements carried out in the workshops and inspection departments of the respective individual firms. The results follow the general pattern set by two similar investigations carried out by the National Physical Laboratory, (N.P.L.), some years ago, but indicate a wider spread of individual errors about the mean size, and correspondingly larger standard deviation. It also indicates that very few firms in the area possess much more sophisticated equipment than micrometers, dial gauges, and slip gauges, and even these are, in the main, neglected and badly maintained. Optical instruments are almost non-existent. The operatives estimation of their accuracy of measurement varies from the N.P.L. findings in that a number are more optimistic, but in general there is a wider and more uniform spread of opinion. The firm's assessments of their employees' capabilities also tend to be optimistic, and in some cases suggest that they do not possess a great deal of knowledge about the ability of their workmen. Another disturbing aspect is the comparison between standard deviation and the tolerances laid down in B.S. 1916, "Limits and Fits for Engineering". This shows that either the tolerances specified by the British Standard are unrealistic, or that industry in this area has difficulty in working to tolerances closer than I.T.7. The investigation has shown that working conditions, and the training of operatives in principles of metrology, leave much to be desired, although the latter point appears to be being remedied since the investigation took place.