Pipe wrench

The pipe wrench, or Stillson wrench is an adjustable wrench used for turning soft iron pipes and fittings with a rounded surface. The design of the adjustable jaw allows it to rock in the frame, such that any forward pressure on the handle tends to pull the jaws tighter together. Teeth angled in the direction of turn dig into the soft pipe. They are not intended for use on hard hex nuts because they would ruin the head; however, when a hex nut becomes rounded beyond use with standard wrenches, the pipe wrench is sometimes used to break the bolt or nut free. Pipe wrenches are usually sold in the following sizes: 10, 14, 18, 24, 36, and 48 inches. They are usually made of either steel or aluminium. Teeth, and jaw kits (which also contain adjustment rings and springs) can be bought to repair broken wrenches, as this is cheaper than buying a new wrench.

These wrenches are sometimes colloquially known as monkey wrenches but this is not technically correct, as the term refers to a specific type of wrench not common anymore, that was designed for nuts rather than pipe. This is occurring in countries such as Australia, where the previous term "Stillson's" or "set of Stillson's" is being progressively replaced in everyday speech by the aforementioned incorrect term.

The U.S. Patent Office issued US patent|95744 to Daniel C. Stillson on 12 October, 1869.

Many companies now manufacture pipe wrenches, but the most prominent professional-grade manufacturer (and the most common in the North American plumbing trade) is RIDGID.fact|date=August 2007

In the UK these wrenches are often described by their size i.e. 18" wrenches are known as "18's", or by the general name of "Stillies". The most prominent professional-grade manufacturer in the UK is RECORD.

ee also

*Adjustable spanner
*Plumber wrench

External links

* [http://www.bochynski.com/stillson/ Biography of Daniel C. Stillson and background on the development of the Stillson wrench.]