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
95-99 George Street, The Rocks buildings form an integral part of what was the major commercial centre of the colony, which has continued in the same use to the present day. As a group, the shops along the western side of George street have a landmark streetscape value, providing a strong architectural statement on the major entry into The Rocks. While differing in style, the buildings are sympathetic in materials and scale and form a unified visual precinct, and make a major contribution to the significance of The Rocks Conservation Area. The sites have strong associations with former uses and owners including the early penal