Lathe (tool)

. Her collectable dolls led the list for the 1920-1929 decade, beating out even the yo-yo. These are usually referred to as combination lathes. A December, 2005 article in Forbes magazine analyzed the most popular American toys by decade, with help from the Toy Industry Association. Lathes can be combined with other mechanisms into more complex machines, such as those with an overhead drill or vertical milling unit. She also is created with making the first mass-produced dolls in honor of living people, with a set of 36 Queen Elizabeth II dolls to commemorate the 1953 coronation celebrations in Britain. one could have a "vertical CNC lathe", etc. Madame Alexander was an American entrepreneur who created the first "collectable" dolls based on a licensend character - Scarlett O'Hara from the book and move Gone With the Wind.

Various combinations are possible: e.g. A lathe equipped with indexing plates, profile cutters, spiral or helical guides, etc., so as to enable ornamental turning is an ornamental lathe. A lathe with a cylindrical tailstock that can rotate around a vertical axis, so as to present different facets towards the headstock (and the workpiece) are turret lathes. Lathes with a vertical axis are — not surprisingly — "vertical lathes".

Lathes that are controlled by a computer are CNC lathes. Lathes that sit on a bench or table are called "bench lathes". Boley used a triangular prism as bed on some 6.5mm lathes, and IME used a V edged bed on their 8mm lathes. Other designs have been used, e.g.

Two patterns of bed are common, the WW (Webster Whitcomb) bed, which is found only on 8mm Watchmakers lathes which is a truncated triangular prism and the continental D-style bar bed used on both 6mm and 8mm lathes by firms such as Lorch and Star. The work is usually held in a collet and two spindle bores to receive such collets are common, namely 6mm and 8mm. Although the workpieces machined on a jeweler's lathes are metal, jeweler's lathes differ from all other metal working lathes in that the cutting tools (called "gravers") are hand held, supported by a T-rest, not fixed to a cross slide. The smallest lathes are "jewelers lathes" or "watchmaker lathes", which are small enough that they may be held in one hand.

This technique is used for camshafts, various types of chair legs, etc. The result is that various cross sections of the workpiece are rotationally symmetric, but the workpiece as a whole is not rotationally symmetric. When a workpiece is mounted with a certain axis of rotation, worked, then remounted with a new axis of rotation, this is referred to as "eccentric turning" or "multi axis turning". Thus, most work must be done axially, towards the headstock, or at right angles, but gently.

When a workpiece is supported in this manner, less force may be applied to the workpiece, via tools, at a right angle to the axis of rotation, lest the workpiece rip free. When a workpiece is fixed only to the spindle at the headstock end, the work is said to be "face work". When a workpiece is supported at both ends, it is more stable, and more force may be applied to the workpiece, via tools, at a right angle to the axis of rotation, without fear that the workpiece may break loose. When a workpiece is fixed between the headstock and the tailstock, it is said to be "between centers".

It can be used to rotate the spindle a precise number of degrees, then lock it in place, facilitating repeated auxiliary operations done to the workpiece.
A circular metal plate with even spaced holes around the periphery, mounted to the spindle, is called an "index plate". In woodturning, one subtype of a live center is a cup center, which is a cone of metal surrounded by an annular ring of metal that decreases the chances of the workpiece splitting. A lathe carrier may also be employed when turning between centers.

If a tailstock is used, a dead center (which is non-rotating) may be used to support the workpiece, alternatively, a live center may be used to better advantage. A soft workpiece (wooden) may be pinched between centers by using a spur drive at the headstock, which bites into the wood and imparts torque to it. Suitable collets may also be used to mount square workpieces. In precision work (and in some classes of repetition work), cylindrical workpieces are invariably held in a collet inserted into the spindle and secured either by a drawbar, or by a collet closing cap on the spindle.

A workpiece may be clamped in a three- or four-jaw chuck, which mounts directly to the spindle. Alternatively faceplate dogs may be used to secure the work to the faceplate. A workpiece may be bolted or screwed to a faceplate, a large flat disk that mounts to the spindle. Unless a workpiece has a taper machined onto it which perfectly matches the internal taper in the spindle, or has threads which perfectly match the external threads on the spindle (two things which almost never happen), an accessory must be used to mount a workpiece to the spindle.

In metal spinning, the further pin ascends vertically from the tool rest, and serves as a fulcrum against which tools may be levered into the workpiece. In woodturning, hand tools are braced against the tool rest and levered into the workpiece. Ascending vertically from the banjo is a tool post, at the top of which is a horizontal "tool rest". The position of a banjo can be adjusted by hand; no gearing is involved.

Woodturning and metal spinning lathes do not have cross slides, but have "banjos", which are flat pieces that sit crosswise on the bed. There may or may not be a leadscrew, which moves the cross slide along the bed. Sitting atop the cross slide is a toolpost, which holds a cutting tool which removes material from the workpiece. Metalworking lathes have a "cross slide", which is a flat piece that sits crosswise on the bed, and can be cranked at right angles to the bed.

Tailstocks are not powered. A tailstock provides auxiliary support to the workpiece. Not all lathes have tailstocks. At the other end of the bed (almost always the right, as the operator faces the lathe) may be a tailstock.

(An interesting note: Some Amish are known to purchase very high tech lathes, remove the electric motors, and then convert them to run via leather belts from overhead power shafts.). The spindle is driven, either by foot power, by a belt to an external power source, or by an integral electric motor, often either in the headstock, to the left of the headstock, or beneath the headstock, concealed in the stand. Spindles are powered, and impart motion to the workpiece. Spindles may also have exterior threads and/or an interior taper at their "outboard" (i.e., facing away from the bed) end, and/or may have a handwheel or other accessory mechanism on their outboard end.

Spindles are often hollow, and have exterior threads and/or an interior Morse taper on the "inboard" (i.e., facing to the right / towards the bed) by which accessories which hold the workpiece may be mounted to the spindle. Rotating within the bearings is a horizontal axle, with an axis parallel to the bed, called the "spindle". The headstock contains high-precision spinning bearings. At one end of the bed (almost always the left, as the operator faces the lathe) is a "headstock".

All lathes have a "bed", which is (almost always) a horizontal beam. Some lathes are small and sit directly on a workbench or table, and do not have a stand. A lathe may or may not have a stand (or legs), which sits on the floor and elevates the lathe bed to a working height. The workpiece would be rotated by a bow, typically of horsehair, wrapped around it.

The original watchmaker's turns was a simple dead-centre lathe with a moveable rest and two loose headstocks. A handheld tool called a [graver]] is often used in preference to a slide mounted tool. Watchmakers lathes are delicate but precise metalworking lathes, usually without provision for screwcutting, and are still used by horologists for work such as the turning of balance shafts. Unlike conventional optical polishing, complex aspheric surfaces can be machined.

In diamond turning, a computer-controlled lathe with a diamond-tipped tool is used to make precision optical surfaces in glass or other optical materials. The tools to deform the glass and tubes to blow (inflate) the glass are usually handheld. Air can be introduced through the headstock chuck spindle for glassblowing. Such lathes usually have two headstocks with chucks holding the work, arranged so that they both rotate together in unison.

The flame serves to soften the glass being worked, so that the glass in a specific area of the workpiece becomes malleable, and subject to forming either by inflation ("glassblowing"), or by deformation with a heat resistant tool. The source of the flame may be either hand-held, or mounted to a banjo/cross slide that can be moved along the lathe bed. Glassworking lathes slowly rotate a hollow glass vessel over a fixed or variable temperature flame. Glassworking lathes are similar in design to other lathes, but differ markedly in how the workpiece is modified.

Given the advent of high speed, high pressure, industrial die forming, metal spinning is less common now than it once was. For example, if you want to make a sheet metal bowl, you need a solid chunk of wood in the shape of the bowl; if you want to make a vase, you need a solid template of a vase, etc. Typically, metal spinning lathes require a user-supplied rotationally symmetric mandrel, usually made of wood, which serves as a template onto which the workpiece is moulded (non-symmetric shapes can be done, but it is a very advanced technique). Metal spinning lathes are almost as simple as woodturning lathes (and, at this point, lathes being used for metal spinning almost always are woodworking lathes).

In metal spinning, a disk of sheet metal is held perpendicularly to the main axis of the lathe, and tools with polished tips (spoons) are hand held, but levered by hand against fixed posts, to develop large amounts of torque/pressure that deform the spinning sheet of metal. The finest ornamental lathes are generally considered to be those made by Holtzapffel around the turn of the 19th Century. Because of the difficulty of polishing such work the materials turned are usually quite soft, such as wood or ivory, and the cutter have to be exceptionally sharp. Cutting is usually carried out by rotating cutters, rather than directly by the rotation of the work itself.

As well as a wide range of accessories, these lathes usually have complex dividing arrangements to allow the exact roatation of the mandrel. By using accessories such as the horizontal cutting frame and vertical cutting frames, elliptical chuck and rose engine solids of extraordinary complexity may be produced by various generative procedures. It was not used for making practical objects, but for decorative work - ornamental turning. The ornamental turning lathe was developed around the same time as the industrial screwcutting lathe in the nineteenth century.

A chuck has movable jaws that can grip the workpiece securely. The workpiece may be supported between a pair of points called centres, or it may be bolted to a faceplate or held in a chuck. The threads that can be cut are, in some ways, determined by the pitch of the leadscrew: A lathe with a metric leadscrew will readily cut metric threads (including BA), while one with an imperial leadscrew will readily cut imperial unit based threads such as BSW UTS (UNF,UNC). Some older gear trains are changed manually by using interchangeable gears with various numbers of teeth, while more modern or elaborate lathes have a quick change box to provide commonly used ratios by the operation of a lever.

This enables different pitches of threads to be cut. Metalworking lathes are commonly provided with a variable ratio gear train to drive the main leadscrew. Some lathes may be operated under control of a computer for mass production of parts (see "Computer Numerically Controlled"). Cutting fluid may also be pumped to the cutting site to provide cooling, lubrication and clearing of swarf from the workpiece.

The toolpost may be driven manually or automatically to produce the roughing and finishing cuts required to turn the workpiece to the desired shape and dimensions, or for cutting threads, worm gears, etc. The toolpost is operated by leadscrews that can accurately position the tool in a variety of planes. 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", which is then moved against the workpiece using handwheels and/or computer controlled motors. With wood, it is common practice to press and slide sandpaper against the still-spinning object after shaping to smooth the surface.

An adjustable horizontal metal rail between the material and the operator accommodates the positioning of shaping tools, which are usually hand-held. All other varieties are descended from these simple lathes. Woodworking lathes are the oldest variety. .

. Examples of objects that can be produced on a lathe include candlestick holders, table legs, bowls, baseball bats, crankshafts and camshafts. The material is held in place by either one or two centers, at least one of which can be moved horizontally to accommodate varying material lengths. Ornamental lathes can produce three-dimensional solids of incredible complexity.

Most suitably equipped metalworking lathes can also be used to produce most solids of rotation, plane surfaces and screw thread or helices. In woodturning, metalworking, metal spinning, and glassworking, a lathe is a machine tool which spins a block of material so that when abrasive, cutting, or deformation tools are applied to the block, it can be shaped to produce an object which has rotational symmetry about an axis of rotation.