science

Pipe wrench

Pipe wrench is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pipe wrench rather than just read about it. In short: 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). The Stillson wrench, or Stillson-pattern wrench, is the usual form of pipe wrench, especially in the US.

Key takeaways

Pipe wrench belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pipe wrench to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pipe wrench from memory before moving on to harder problems.

Reference excerpt

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). The Stillson wrench, or Stillson-pattern wrench, is the usual form of pipe wrench, especially in the US. The Stillson name is that of the original patent holder, who licensed the design to a number of manufacturers; the patent has since expired. A different type of wrench with compound leverage often used on pipes, the plumber wrench, is also called a "pipe wrench" in some places.

Description The Stillson wrench is an adjustable wrench (spanner) with hardened serrated teeth on its jaws. The hard teeth bite into the softer metal of the round pipe and provide the grip needed to turn a pipe, even against fair resistance. The design of the adjustable jaw, which permits a certain amount of intentional play out of square, allows it to bind on the pipe, with forward pressure on the handle pulling the jaws tighter. On some models, two leaf springs, above and below the knurled adjusting knob, help unlock the jaw when pressure on the handle of the wrench is released. Pipe wrenches are not intended for regular use on hex nuts or other fittings. However, if a hex nut becomes rounded (stripped) so that it cannot be moved by standard wrenches, a pipe wrench can be used to free the bolt or nut, because the pipe wrench is designed to bite into rounded metal surfaces. Pipe wrenches are classified by the length of the handle. They are generally available in sizes from 6 inches (150 mm) to 48 inches (1,200 mm) or larger. They are usually made of forged steel. Today, aluminium might be substituted to reduce the weight of the body of the wrench, although the teeth and jaw remain steel. Teeth and jaw kits (which also contain adjustment rings and springs) can be bought to repair broken wrenches.

History

Daniel C. Stillson (1826–1899), a mechanic at the Walworth Company, in Cambridge, Massachusetts, created the first such wrench. On October 12, 1869, US patent #95,744 was issued to Stillson. On 17 August 1888, the Swedish inventor Johan Petter Johansson (1853–1943) took out his first patent on the adjustable pipe wrench. The Swedish Patent Office issued the patent again in 1894. The idea emerged after he established his company Enköpings Mekaniska Verkstad. Back then, nut dimensions were poorly standardized, so each time a tradesman was out on a job, he needed a trolley to take a set of fixed pipe wrenches with him. Johansson's tool could grip nuts of different dimensions.

Pipe wrench in different countries

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. In Spain and Morocco, they are called grifa. In Mexico they are known and called "stillson" without even using the word llave ("wrench"). In Turkey they are known as "English Keys".

See also Adjustable wrench – a straight-jawed adjustable wrench with jaws in line with its handle Monkey wrench – a straight-jawed adjustable wrench similar to a pipe wrench and often confused with it Nipple wrench (plumbing) – a pipe wrench that grabs the interior of a pipe, rather than the exterior Plumber wrench – a wrench used for turning pipes and tightening hex nuts

References

External links Biography of Daniel C. Stillson and background on the development of the Stillson wrench. Adjustable wrenches review

Illustrations

Worked examples

Example 1 — a first encounter with Pipe wrench

Start with the simplest possible case. Write down what Pipe wrench claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pipe wrench before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pipe wrench ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pipe wrench

In research: Pipe wrench appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pipe wrench in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pipe wrench is common in secondary-school and first-year university syllabi. It links to neighbouring topics American inventions, Piping, Plumbing, so understanding it makes those chapters shorter.
In everyday life: Look for Pipe wrench outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pipe wrench in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pipe wrench means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pipe wrench out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pipe wrench in simple terms?

Why does Pipe wrench matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pipe wrench?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pipe wrench.