Rockwell scale 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 tensile strength. This important relation permits economically important nondestructive testing of
123-125 George Street, The Rocks Free Classical style, executed to give a sense of decorum to what would otherwise have been simple commercial / residential structures. The buildings have streetscape value as two buildings in a group of three that were designed to appear as one property. The buildings' scale and alignment to the street are typical of that found along the business precinct of George Street in The Rocks area. The street façades have remained relatively intact since they were constructed in 1882. The place has a strong or special association with a particular community or cultural group in New South Wales for social,