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
The Rocks Crumble The Rocks Crumble The Rocks Crumble is the eighth Jandek album, released as Corwood 0746. It is his third release of 1983, and is the first Jandek album to feature extensive use of drums and electric guitar. It was reissued on CD in 2001. "The Rocks Crumble" marks the beginning of what is often referenced as Corwood's "first electric period," since the majority of the album is played on electric guitar with clattering, earsplitting drums behind it. That said, Jandek eases us into this new phase gently, and its approach echoes the cover, in which an old Slingerland drum set