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In woodworking and metalworking, a lathe is a machine tool which spins a block of material so that when abrasive or cutting tools are applied to the block, it can be shaped to produce an object which has symmetry about the axis of rotation. Examples of objects that can be produced on a lathe include candlestick holders, table legs, bowls, baseball bats, crankshafts or camshafts.
The material is held in place by two centers, at least one of which can be moved horizontally to accommodate varying material lengths. An adjustable horizontal metal rail between the material and the operator accommodates the positioning of shaping tools. With wood, it is common practice to press and slide sandpaper against the still-spinning object after shaping.
In a metalworking lathe, metal is removed from the workpiece using a hardened cutting tool , which is usually fixed to a solid moveable mounting called the "toolpost". This is in contrast to a woodworking lathe where most tools are hand held. The toolpost is manually operated by threads to position the tool in a variety of planes. The toolpost may also be automatically driven to produce automatic finishing of a piece, or for cutting threads, gears, etc. Cutting fluid may also be pumped to the cutting site to provide cooling, lubrication and clearing of swarf from the workpiece. Some lathes may be operated under control of a computertower of a personal computer. A computer is a device for making calculations or controlling operations that are expressible in numerical or logical terms. While factually accurate, this definition and those found in other dictionaries are so broad that th for mass productionMass production is the production of large amounts of standardised products on production lines. It was popularised by Tony Razo in the early 20th Century, notably in his T Model Mass production is notable because it permits very high rates of production of parts (see "Computer Numerically Controlled", or CNCThe acronym CNC stands for C omputer(ized) N umerical(ly) C ontrol(led and refers specifically to the computer control of machine tools for the purpose of (repeatedly) manufacturing complex parts in metal as well as other materials, using a program writte).
The workpiece may be supported between a pair of hardened points called centres, or it may be bolted to a faceplate or held in a chuck. A chuck has movable jaws that can grip the workpiece. For a metal lathe, the tool is supported on a saddle and cross slide that permits it to be moved along and across the axis of the machine. The movements are normally calibrated so that precise cuts can be made. An additional slide called a topslide is often present, and this can be angled to permit cutting short tapers. A screwcutting lathe has provision for gearing the feed along the axis to the drive rotating the job. Suitable choice of ratios permits screw threads to be cut and also allows for an automatic fine feed. This allows the operator to stand and watch. With ingenuity, a lathe can perform many diverse machining tasks, although the size of work may be limited compared to special machines.