Rockwell scale for specialized applications. There are special scales for measuring case-hardened specimens. Rockwell scale The Rockwell scale is a hardness scale based on indentation hardness of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale (see below). When testing metals, indentation hardness correlates linearly with
Worshipful Company of Scientific Instrument Makers or using scientific instruments. This could be any kind of scientific instrument: a measuring instrument, like a feeler gauge or an atomic clock, or an imaging instrument like a PET scanner. It might even be a piece of control engineering incorporating many instruments. What makes the Company a community is partly a shared interest in scientific instruments and, more generally, in science and engineering. It is also partly a shared love of good company, of meeting for discussion over food and wine, and of bringing partners or guests to a grand banquet in distinguished surroundings. But what makes the Company