Discussion on "The influence of mass production on design" at the Manchester Section of the Institution

MR. PUDGE said that he would like to ask Mr. Brazenall a question with regard to high carbon chrome steel lending itself to the manufacture of broaches, etc. One can get uniform heat treatment and saturation, and also uniform quenching, but is it not necessary to protect the sharp edges in some way? Otherwise it would appear that such portions are liable to burn. MR. BRAZENALL replied that in the case of a broach with an acute angle of 60 degrees it was usual to heat in a compound of some kind, such as ordinary charcoal. No bone "dust" should be used on account of the penetration of the carbon.