When metals such as steel, brass, iron, and so forth need to be machined, notched or cut, the process is accomplished using a metal lathe. There are various types of metal lathes for various purposes and tolerances, but the most common metal lathe is a large, heavy-duty piece of equipment consisting of a number of components including: 1) the headstock, 2) bed, 3) feed and leadscrews, 4) carriage, 5) cross slide, 6) compound rest, 7) toolpost, and 8) tailstock. Each of these parts provides a vital function in the operation of the metal lathe.
In very basic terms, a piece of metal, ordinarily called stock, is inserted into the spindle of the lathe and the spindle, enclosed by the headstock, is rotated at a set speed. Pre-selected cutting bits made of carbide or other hardened material, are held rigidly in place by the toolpost. The bits, positioned and controlled by the carriage mechanism, are automatically set against the rotating material to begin cutting. The rotating stock is suspended inside the bed and may be moved back and forth by the feedscrew and leadscrew as the machining bits are engaged, disengaged and repositioned by the cross slide and the compound rest.
With the advent of plastics and alloys, the metal lathe must be much more versatile than it was at its inception in the early 19th century. Henry Maudsley is generally credited as the inventor of the modern metal lathe,
There are today, many types and variations of the metal lathe, each designed for a particular function and/or tolerance. Some of the more common types of lathes are: the center lathe which is the simplest of lathes as well as the largest; the bench lathe that is usually small enough to be mounted on a workbench; the turret lathe which allows multiple bits to be simultaneously engaged. Other less versatile lathes that are used for more specialized operations include the engine lathe, the tool room lathe, the capstan lathe and the multi-spindle lathe
Computer technology has given the metal lathe a huge range of versatility, economy and ease of operation. The CNC lathe, a computer-operated machine, allows an operator to simply program a particular function of the machining process. With the press of a button, the CNC lathe will automatically set the proper speed of the spindle rotation and engage the designated number of machining bits at precisely the right angle and depth. Today, the CNC lathe is the most commonly used metal lathe.