Discussion on "Recent developments in the measurement and control of surface roughness" at the Coventry Section of the Institution

MR. H. E. WEATHERLEY : It is indeed a surprise to be asked to open this discussion. I am afraid Mr. Shaw has got me rather confused with his graphs, so that I find difficulty in sorting it all out. But I congratulate Mr. Shaw on the thoroughness of his paper, and I should like to know whether those graphs are all in relation, i.e., in proportion. (MR. SHAW : Yes, in the original records the heights of the roughnesses are magnified 2,000 times and the horizontal distances 32 times). Have you tried Episcopical methods of checking surfaces ? To me they seem much easier, quicker, and more practical from the shop point of view ; that is, if a parallel beam with Episcopical attachment is used, with a fixed magnification you are able, provided that your projection is accurate, to measure the width on your graph quite easily.