Editing Lathe (section)

== Uses ==

=== Woodworking ===
[[File:Woodlathe.JPG|thumb|right|A modern woodworking lathe]]
[[File:CNC Wood Lathe CNC Wood Turning Machine.jpg|thumb|CNC wood lathe]]
[[File:JaquesCookStaunton.jpg|thumb|right|[[Chess pieces]] may be manufactured by way of a lathe.]]

Woodworking lathes are the oldest variety, apart from pottery wheels. All other varieties are descended from these simple lathes. An adjustable horizontal metal rail, the tool-rest, between the material and the operator accommodates the positioning of shaping tools, which are usually hand-held. After shaping, it is common practice to press and slide sandpaper against the still-spinning object to smooth the surface made with the metal shaping tools. The tool-rest is usually removed during sanding, as it may be unsafe to have the operators hands between it and the spinning wood.{{citation needed|date=October 2019}}

Many woodworking lathes can also be used for making bowls and plates. The bowl or plate needs only to be held at the bottom by one side of the lathe. It is usually attached to a metal face plate attached to the spindle. With many lathes, this operation happens on the left side of the headstock, where are no rails and therefore more clearance. In this configuration, the piece can be shaped inside and out. A specific curved tool-rest may be used to support tools while shaping the inside. Further detail can be found on the [[woodturning]] page.

Most woodworking lathes are designed to be operated at a speed of between 200 and 1,400 revolutions per minute, with slightly over 1,000 rpm considered optimal for most such work, and with larger workpieces requiring lower speeds.<ref name="Conover2000">{{citation|author=Ernie Conover|title=Turn a Bowl with Ernie Conover: Getting Great Results the First Time Around|url=https://books.google.com/books?id=YNGOirjO8NgC&pg=PA16|year=2000|publisher=Taunton|isbn=978-1-56158-293-8|page=16}}</ref>

=== Duplicating ===
{{main|Copying lathe}}
[[File:Harpers Ferry gun smith shop - Blanchard lathe - 01.jpg|thumb|Water-powered Blanchard lathe used for duplicating gun stocks from the 1850s. [[Harpers Ferry Armory]].]]
One type of specialized lathe is duplicating or copying lathe. Some types of them are known as Blanchard lathe, after [[Thomas Blanchard (inventor)|Thomas Blanchard]]. This type of lathe was able to create shapes identical to a standard pattern and it revolutionized the process of gun [[Stock (firearm)|stock]] making in the 1820s when it was invented.<ref>{{cite book|last1=Smith|first1=Merritt Roe|title=Harpers Ferry Armory and the New Technology: The Challenge of Change|date=2015|publisher=Cornell University Press|isbn=9780801454394|url=https://books.google.com/books?id=D_RqBgAAQBAJ&pg=PP1|access-date=30 June 2016}}</ref>

The [[Hermitage Museum]], Russia displays the copying lathe for [[ornamental turning]]: making medals and [[Guilloché|guilloche]] patterns, designed by [[Andrey Nartov]], 1721.<ref>{{Cite web|url=https://ornamentalturning.net/early_modern_russia_turners.html|title=Ornamental Turning - Turners of the Early Modern Period in Russia|website=ornamentalturning.net}}</ref><ref>Book review of: ''Nartov and his Theatrum Machinarium'' (translated from Russian in 1966);  {{doi|10.2307/3102014}}, {{JSTOR|3102014}}
</ref>

=== Patternmaking ===
[[File:Patternmaker's double lathe (Carpentry and Joinery, 1925).jpg|thumb|Patternmaker's double lathe (Carpentry and Joinery, 1925)]]

Used to make a [[Pattern (casting)|pattern]] for [[foundries]], often from wood, but also plastics. A patternmaker's lathe looks like a heavy wood lathe, often with a turret and either a [[leadscrew]] or a rack and [[pinion]] to manually position the [[Turret lathe|turret]]. The turret is used to accurately cut straight lines. They often have a provision to turn very large parts on the other end of the headstock, using a free-standing toolrest. Another way of turning large parts is a sliding bed, which can slide away from the headstock and thus open up a gap in front of the headstock for large parts.

=== Metalworking ===
{{Main|Metal lathe}}

In a [[Lathe (metal)|metalworking lathe]], metal is removed from the workpiece using a hardened [[tool bit|cutting tool]], which is usually fixed to a solid moveable mounting, either a tool-post or a turret, which is then moved against the workpiece using handwheels or computer-controlled motors. These cutting tools come in a wide range of sizes and shapes, depending upon their application. Some common styles are diamond, round, square and triangular.

The tool-post is operated by lead-screws that can accurately position the tool in a variety of planes. The tool-post 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 [[screw thread|threads]], [[worm gear]]s, etc. [[Cutting fluid]] may also be pumped to the cutting site to provide cooling, lubrication and clearing of [[swarf]] from the workpiece. Some [[Lathe (metal)#CNC lathe|lathes]] may be operated under control of a [[computer]] for [[mass production]] of parts (see "[[CNC|Computer numerical control]]").

Manually controlled metalworking lathes are commonly provided with a variable-ratio gear-train to drive the main lead-screw. This enables different [[Screw thread#Lead, pitch, and starts|thread pitches]] to be cut. On some older lathes or more affordable new lathes, the gear trains are changed by swapping gears with various numbers of teeth onto or off of the shafts, while more modern or expensive manually controlled lathes have a '''quick-change box''' to provide commonly used ratios by the operation of a lever. CNC lathes use computers and servomechanisms to regulate the rates of movement.

On manually controlled lathes, the thread pitches that can be cut are, in some ways, determined by the pitch of the lead-screw: A lathe with a [[metre|metric]] lead-screw will readily cut metric threads (including [[British Association screw threads|BA]]), while one with an imperial lead-screw will readily cut [[Imperial unit#Measures of length|imperial-unit]]-based threads such as [[British Standard Whitworth|BSW]] or [[Unified Thread Standard|UTS]] (UNF, UNC). This limitation is not insurmountable, because a 127-tooth gear, called a transposing gear, is used to translate between metric and inch thread pitches. However, this is optional equipment that many lathe owners do not own. It is also a larger change-wheel than the others, and on some lathes may be larger than the change-wheel mounting banjo is capable of mounting.

The workpiece may be supported between a pair of points called [[Lathe center|centres]], or it may be bolted to a faceplate or held in a [[Chuck (engineering)|chuck]]. A chuck has movable jaws that can grip the workpiece securely.

There are some effects on material properties when using a metalworking lathe. There are few chemical or physical effects, but there are many mechanical effects, which include residual stress, micro-cracks, work-hardening, and tempering in hardened materials.

=== Cue lathes ===

Cue lathes function similarly to turning and spinning lathes, allowing a perfectly radially-symmetrical cut for [[cue stick|billiard cues]]. They can also be used to refinish cues that have been worn over the years.

=== Glass-working ===

Glass-working lathes are similar in design to other lathes, but differ markedly in how the workpiece is modified. Glass-working lathes slowly rotate a hollow glass vessel over a fixed- or variable-temperature flame. 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. The flame serves to soften the glass being worked, so that the glass in a specific area of the workpiece becomes ductile and subject to forming either by inflation ("[[glassblowing]]") or by deformation with a heat-resistant tool. Such lathes usually have two head-stocks with chucks holding the work, arranged so that they both rotate together in unison. Air can be introduced through the headstock chuck spindle for glassblowing. The tools to deform the glass and tubes to blow (inflate) the glass are usually handheld.

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. Unlike conventional optical grinding, complex [[aspheric lens|aspheric]] surfaces can be machined easily. Instead of the dovetailed ways used on the tool slide of a metal-turning lathe, the ways typically float on air bearings, and the position of the tool is measured by optical interferometry to achieve the necessary standard of precision for optical work. The finished work piece usually requires a small amount of subsequent polishing by conventional techniques to achieve a finished surface suitably smooth for use in a lens, but the rough grinding time is significantly reduced for complex lenses.

=== Metal-spinning ===
{{Main|metal spinning}}

In [[metal spinning]], a disk of sheet metal is held perpendicularly to the main axis of the lathe, and tools with polished tips (''spoons'') or roller tips are hand-held, but levered by hand against fixed posts, to develop pressure that deforms the spinning sheet of metal.

Metal-spinning lathes are almost as simple as wood-turning lathes. Typically, metal spinning requires a mandrel, usually made from wood, which serves as the template onto which the workpiece is formed (asymmetric shapes can be made, but it is a very advanced technique). For example, to make a [[sheet metal]] bowl, a solid block of wood in the shape of the bowl is required; similarly, to make a [[vase]], a solid template of the vase is required.

Given the advent of high-speed, high-pressure, industrial die forming, metal spinning is less common now than it once was, but still a valuable technique for producing one-off prototypes or small batches, where die forming would be uneconomical.

=== Ornamental turning ===
{{main|Ornamental turning}}

The ornamental turning lathe was developed around the same time as the industrial screw-cutting lathe in the nineteenth century. It was used not for making practical objects, but for [[decorative]] work: ''ornamental turning''. By using accessories such as the horizontal and vertical [[cutting frame]]s, eccentric [[chuck (engineering)|chuck]] and elliptical chuck, solids of extraordinary complexity may be produced by various generative procedures.

A special-purpose lathe, the [[Rose engine lathe]], is also used for ornamental turning, in particular for engine turning, typically in precious metals, for example to decorate pocket-watch cases. As well as a wide range of accessories, these lathes usually have complex dividing arrangements to allow the exact rotation of the mandrel. Cutting is usually carried out by rotating cutters, rather than directly by the rotation of the work itself. Because of the difficulty of polishing such work, the materials turned, such as wood or ivory, are usually quite soft, and the cutter has to be exceptionally sharp. The finest ornamental lathes are generally considered to be those made by [[Holtzapffel]] around the turn of the 19th century.

=== Reducing ===

Many types of lathes can be equipped with accessory components to allow them to reproduce an item: the original item is mounted on one spindle, the blank is mounted on another, and as both turn in synchronized manner, one end of an arm "reads" the original and the other end of the arm "carves" the duplicate.

A '''reduction lathe''' is a specialized lathe that is designed with this feature and incorporates a mechanism similar to a [[pantograph]], so that when the "reading" end of the arm reads a detail that measures one inch (for example), the cutting end of the arm creates an analogous detail that is (for example) one quarter of an inch (a 4:1 reduction, although given appropriate machinery and appropriate settings, any reduction ratio is possible).

Reducing lathes are used in coin-making, where a plaster original (or an epoxy master made from the plaster original, or a copper-shelled master made from the plaster original, etc.) is duplicated and reduced on the reducing lathe, generating a [[Coining (mint)#Modern die production|master die]].

=== Rotary lathes ===

A lathe in which wood logs are turned against a very sharp blade and peeled off in one continuous or semi-continuous roll. Invented by [[Immanuel Nobel]] (father of the more famous [[Alfred Nobel]]). The first such lathes in the United States  were set up in the mid-19th century. The product is called [[wood veneer]] and it is used for making [[plywood]] and as a cosmetic surface veneer on some grades of [[particle board|chipboard]].

=== Watchmaking ===

Watchmakers lathes are delicate but precise metalworking lathes, usually without provision for [[screw]]cutting, and are still used by [[horologist]]s for work such as the turning of balance staffs. A handheld tool called a [[hand engraving|graver]], supported by a tool-rest, is often used in preference to a slide-mounted tool. The original watchmaker's turns was a simple [[dead-center lathe]] with a moveable rest and two loose head-stocks. The workpiece would be rotated by a bow, typically of [[horsehair]], wrapped around it.

=== Transcription or recording ===
{{main|Disc cutting lathe}}

Transcription or recording [[Disc cutting lathe|lathes]] are used to make grooves on a surface for recording sounds. These were used in creating sound grooves on wax cylinders and then on flat recording discs originally also made of wax, but later as [[Acetate disc|lacquers]] on a substratum. Originally the cutting lathes were driven by sound vibrations through a horn in a process known as [[Phonograph record#Acoustic recording|acoustic recording]] and later driven by an electric current when [[microphone]]s were first used in sound recording. Many such lathes were professional models, but others were developed for home recording and were common before the advent of home tape recording.