Pipe wrench Pipe wrench A pipe wrench is any of several types of wrench that are designed to turn threaded pipe and pipe fittings for assembly (tightening) or disassembly (loosening). Especially in North America, the Stillson wrench or Stillson-pattern wrench is the usual form of pipe wrench. (The name comes from the original patent holder, who licensed the pattern to multiple manufacturers; the patent expired decades ago.) Another type of wrench often used on pipes, the plumber wrench, is also often called a pipe wrench, depending on locale. The Stillson type is an adjustable wrench/spanner with hardened serrated teeth on its jaws;
Tool stone Tool stone In archaeology, a tool stone is a type of stone that is used to manufacture stone tools, or stones used as the raw material for tools. Generally speaking, tools that require a sharp edge are made using cryptocrystalline materials that fracture in an easily controlled conchoidal manner. Cryptocrystalline tool stones include flint and chert, which are fine-grained sedimentary materials; rhyolite and felsite, which are igneous flowstones; and obsidian, a form of natural glass created by igneous processes. These materials fracture in a predictable fashion, and are easily resharpened. For more information on this subject, see lithic reduction. Large-grained