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
105 George Street, The Rocks at 105 George Street, are of State heritage significance for their historical and scientific cultural values. The site and building are also of State heritage significance for their contribution to The Rocks area which is of State Heritage significance in its own right. 105 George Street is a reconstructed, typical example of a simple 19th century shop and residence. The building has been used for commercial purposes for more than 150 years. The building makes an important contribution to the surrounding 19th century commercial precinct and contributes to the character of the surrounding area of The Rocks. 105 George Street,