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
121 George Street, The Rocks and has been continuously occupied for commercial and retail purposes since construction in 1880. The building's scale and alignment to the street is typical of that found along the west side of George street and lining the harbourside as part of the business precinct of The Rocks. The building is part of the rich fabric of The Rocks which is highly regarded by residents, Sydney people and visitors and acknowledged by the Australian Heritage Commission and the National Trust as part of The Rocks Urban Conservation Area. The building at 121 George street is expressive of the close weaving of