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Pipe wrench

new pipe wrench
1869 patent drawing.

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 (by length of handle): 10, 14, 18, 24, 36, and 48 inches, although smaller and larger sizes are available as well. 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.

In countries such as Australia and the United Kingdom, the previously common term "Stillson's" or "set of Stillson's" is being progressively replaced in everyday speech by the colloquial term monkey wrenches. This usage is not technically correct, as the term "monkey wrench" refers to a now uncommon type of adjustable wrench that was designed for use with nuts rather than with round pipes.

In South Africa, the terms "bobbejaan spanner" and "baboon spanner" are commonly used, especially for large pipe wrenches. "Bobbejaan" is the Afrikaans term for a baboon.

The U.S. Patent Office issued U.S. Patent 95,744 to Daniel C. Stillson on 12 October 1869.

Three old Stillson wrenches

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/stills".

In popular culture pipe wrenches are frequently shown as bludgeoning weapons.

It should be noted that in Prince Edward Island, Canada there is some controversy over the true creator of the wrench. In Island folklore, the wrench was developed by Owen "Iney" McCluskey[1] (or McCloskey[2]), although no proof has ever been presented that would suggest that McCluskey and Stillson ever met.


  1. ^ McIssac, Leo (Fall/Winter 1995). "McCluskey's Wrench". Island Magazine. 
  2. ^ "BURIAL SITES OF INTERESTING PEOPLE ON PRINCE EDWARD ISLAND — HISTORIC SITES AND MONUMENTS". Archived from the original on 2009-01-20. Retrieved 2009-01-20. 


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