Machine tool

A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by the selective removal of metal.

Examples of machine tools are:

• lathe (work rotates, single-edge cutter is fixed)
• mill (work is fixed, multi-edge cutter rotates)
• drill (like mill, but optimized to make holes)
• surface grinder
• broach
• gear shaper
• shaper
• Stewart Platform mills
• hobbing machine

Machine tools can be operated manually, or under automatic control. When operated directly by computers, they are referred to as CNC for computer numerical control machine tools.

When fabricating or shaping parts, several techniques are used to remove unwanted metal. Among these are:

• single edge cutting tools
• multiple edge cutting tools
• grinding
• EDM (electrical discharge machining)

Several regions of the United States became centers for machine tool development, including Cincinnati, Ohio and Springfield, Vermont.