Discussion on "The cost of fine accuracy" at the Glasgow Section of the Institution

MR. MACFARLANE: The author mentions one firm in Germany on Diesel work using the tolerance of .00001 inch. I will not ask him how this firm claims to measure that great degree of accuracy under commercial conditions as here you have got to go to places like the N.P.L. to get any guarantee of anything finer than l/100,000th of an inch. We ought to keep in mind that such measuring machines require very special treatment and are put up in special buildings on special foundations at special temper - tures and proof against vibration. I was interested in the cinematograph machine. I know a firm who were faced with this trouble and they had to use optical means of testing to get the degree of accuracy. I think the trouble in that case is that you get undertones which seriously mar the hearing.