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 bit finished turn. Opposing tool bits may be used (instead of a rest) to cancel each other's deflecting forces (called a "balanced turning tool"), in which case the box tool begins to overlap in form, function, and identity with a hollow mill. Shapers, slotters, and planers often employ a kind of toolholder called a "clapper box" that swings freely on the return stroke of the ram or bed. On the next cutting stroke, it "claps" back into cutting position. Its movement is analogous to that of a butterfly-style check valve. Fly cutters are a type of milling cutter in which one