Tool

This article is about the instrument. For the band, see Tool (band). For other uses, see Tool (disambiguation).

A modern hammer is directly descended from ancient hand tools

A tool is a piece of equipment that typically provides a mechanical advantage in accomplishing a task or enables the accomplishment of a task not otherwise possible. The most basic tools are simple machines. For example, a crowbar simply functions as a lever. The further out from the pivot point, the more force is transmitted along the lever. When particularly intended for domestic use, a tool is often called a utensil.

Observation has confirmed that multiple species can use tools, including monkeys, apes, several birds, sea otters, and others. Philosophers originally thought that only humans had the ability to make tools, until zoologists observed birds and monkeys making tools. Now humans' unique relationship to tools is considered to be that we are the only species that uses tools to make other tools.

Most anthropologists believe that the use of tools was an important step in the evolution of mankind. Humans evolved an opposable thumb - useful in holding tools - and increased dramatically in intelligence, which aided in the use of tools.

Some tools can also serve as weapons, such as a hammer or a knife. Similarly, people can use weapons, such as explosives, as tools.

Functions

Tools often employ the principles of a simple machine, which is a device that only requires the application of a single force to work. Many tools or groups of tools serve to perform one or more of a set of basic operations, such as:

• Cutting tools, such as the knife, scythe or sickle, are wedge-shaped implements that produce a shearing force along a narrow face. Ideally, the edge of the tool needs to be harder than the material being cut or else the blade will become dulled with repeated use. But even resilient tools will require periodic sharpening, which is the process of removing deformation wear from the edge.
• Concentrating force tools, such as the hammer, maul and whip operate by applying physical compression to a surface. In the case of the screwdriver, this force is applied by means of torque. Writing implements deliver a fluid to a surface, and may require some compression to activate.
• Guiding and measuring tools include the set square, straightedge and theodolite.
• Protecting tools include all personal protective equipment, such as gloves, safety glasses, ear defenders and biohazard suits.
• Seizing and holding (pliers, glove, wrench, etc...)

Tool substitution

Often, by design or coincidence, a tool may share key functional attributes with one or more other tools. In this case, some tools can substitute for other tools, either as a make-shift solution or as a matter of practical efficiency. "One tool does it all" is a motto of some importance for workers who cannot practically carry every specialized tool to the location of every work task. Tool substitution may be divided broadly into two classes: substitution "by-design", or "multi-purpose" use, and substitution as make-shift. In many cases, the designed secondary functions of tools are not widely known. As an example of the former, many wood-cutting hand saws integrate a carpenter's square by incorporating a specially shaped handle which allows 90° and 45° angles to be marked by aligning the appropriate part of the handle with an edge and scribing along the back edge of the saw. The latter is illustrated by the saying "All tools can be used as hammers." Nearly all tools can be re purposed to function as a hammer, even though very few tools are intentionally designed for it.

Multi-use tools

• A Multitool is a hand tool that incorporates several tools into a single, portable device.
• Lineman's pliers incorporate a gripper and cutter, and are often used secondarily as a hammer.
• Hand saws often incorporate the functionality of the carpenter's square in the right-angle between the blade's dull edge and the saw's handle.

History

Main article: History of technology

Evidence of stone tool manufacture and use dates from the start of the Stone Age, though it is possible that earlier tools of less durable material have not survived. The earliest tools were made by now-extinct hominid species preceding Homo sapiens. Stone tools found in China magnetostratigraphically date back to approximately 1.36 million years ago. The transition from stone to metal tools roughly coincided with the development of agriculture around the 4th millennium BC.

Mechanical devices experienced a major expansion in their use in the Middle Ages with the systematic employment of new energy sources: water (waterwheels) and wind (windmills).

Machine tools occasioned a surge in producing new tools in the industrial revolution. Advocates of nanotechnology expect a similar surge as tools become microscopic in size.

See also

• Device paradigm
• Toolmaker
• List of tool-lending libraries
• Toolbank
• Category:Tool-using species