Metal lathe or metalworking lathe are generic terms for any of a large class of lathes designed for precisely machining relatively hard materials. A lathe (ˈleɪð is a Machine tool which spins a block of material to perform various operations such as Cutting, Sanding, Knurling Conventional Machining, one of the most important material removal methods is a collection of material-working processes in which power-driven Machine tools, such as lathes They were originally designed to machine metals; however, with the advent of plastics and other materials, and with their inherent versatility, they are used in a wide range of applications, and a broad range of materials. The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products In machining jargon, where the larger context is already understood, they are usually simply called lathes, or else referred to by more-specific subtype names (toolroom lathe, turret lathe, etc. For Wikipedia jargon see WikipediaGlossary. For hacker slang see Jargon File. ). These rigid machine tools remove material from a rotating workpiece via the (typically linear) movements of various cutting tools, such as tool bits and drill bits. A machine tool is a powered mechanical device typically used to fabricate metal components of machines by Machining, which is the selective removal of metal A rotation is a movement of an object in a circular motion A two- Dimensional object rotates around a center (or point) of rotation The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, Shapers and planers. For the ficitonal character see Drill Bit (Transformers. Drill bits are cutting tools used to create cylindrical holes
Construction
The machine has been greatly modified for various applications however a familiarity with the basics shows the similarities between types. These machines consist of, at the least, a headstock, bed, carriage and tailstock. The better machines are solidly constructed with broad bearing surfaces (slides or ways) for stability and manufactured with great precision. This helps ensure the components manufactured on the machines can meet the required tolerances and repeatability.
Headstock
The headstock (H1) houses the main spindle (H4), speed change mechanism (H2,H3), and change gears (H10). The headstock is required to be made as robust as possible due to the cutting forces involved, which can distort a lightly built housing, and induce harmonic vibrations that will transfer through to the workpiece, reducing the quality of the finished workpiece. In Acoustics and Telecommunication, the harmonic of a Wave is a component Frequency of the signal that is an Integer
The main spindle is generally hollow to allow long bars to extend through to the work area, this reduces preparation and waste of material. The spindle then runs in precision bearings and is fitted with some means of attaching work holding devices such as chucks or faceplates. A chuck is a specialised type of clamp used to hold rotating tools or materials A lathe faceplate is the basic workholding accessory for a wood or metal turning lathe. This end of the spindle will also have an included taper, usually morse, to allow the insertion of tapers and centers. A machine taper is a system for securing cutting bits and other accessories to a machine tool's powered rotating spindle A machine taper is a system for securing cutting bits and other accessories to a machine tool's powered rotating spindle A lathe center (or center) is a tool that has been ground to an included angle of 60 ° and is used to accurately position a workpiece about its axis On older machines the spindle was directly driven by a flat belt pulley with the lower speeds available by manipulating the bull gear, later machines use a gear box driven by a dedicated electric motor. A Belt is a looped strip of flexible material used to mechanically link two or more rotating shafts A pulley (also called a sheave or block) is a Wheel with a groove between two Flanges around its Circumference The fully geared head allows the speed selection to be done entirely through the gearbox
Bed
The bed is a robust base that connects to the headstock and permits the carriage and tailstock to be aligned parallel with the axis of the spindle. This is facilitated by hardened and ground ways which restrain the carriage and tailstock in a set track. The carriage travels by means of a rack and pinion system, leadscrew of accurate pitch, or feedscrew. A rack and pinion is a pair of Gears which convert rotational motion into linear motion A screw is a shaft with a helical groove or thread formed on its surface and provision at one end to turn the screw
Feed and lead screws
The feedscrew (H8) is a long driveshaft that allows a series of gears to drive the carriage mechanisms. These gears are located in the apron of the carriage. Both the feedscrew and leadscrew (H9) are driven by either the change gears (on the quadrant) or an intermediate gearbox known as a quick change gearbox (H6) or Norton gearbox. A leadscrew is a screw specialized for the purpose of translating rotational to linear motion These intermediate gears allow the correct ratio and direction to be set for cutting threads or worm gears. A screw is a shaft with a helical groove or thread formed on its surface and provision at one end to turn the screw A worm drive is a gear arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm gear (which is Tumbler gears (operated by H5) are provided between the spindle and gear train along with a quadrant plate that enables a gear train of the correct ratio and direction to be introduced. This provides a constant relationship between the number of turns the spindle makes, to the number of turns the leadscrew makes. This ratio allows screwthreads to be cut on the workpiece without the aid of a die. Taps and dies are cutting tools used to create Screw threads in solid substances including but not limited to Metal, Wood, and Plastic.
The leadscrew will be manufactured to either imperial or metric standards and will require a conversion ratio to be introduced to create thread forms from a different family. Imperial units or the Imperial system is a collection of units first defined in the British Weights and Measures Act of 1824 The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International To accurately convert from one thread form to the other requires a 127-tooth gear, or on lathes not large enough to mount one, an approximation may be used. Multiples of 3 and 7 giving a ratio of 63:1 can be used to cut fairly loose threads. This conversion ratio is often built into the quick change gearboxes.
Carriage
In its simplest form the carriage holds the tool bit and moves it longitudinally (turning) or perpendicularly (facing) under the control of the operator. The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, Shapers and planers. The operator moves the carriage manually via the handwheel (5a) or automatically by engaging the feedscrew with the carriage feed mechanism (5c), this provides some relief for the operator as the movement of the carriage becomes power assisted. The handwheels (2a, 3b, 5a) on the carriage and its related slides are usually calibrated, both for ease of use and to assist in making reproducible cuts.
Cross-slide
(3) The cross-slide stands atop the carriage and has a leadscrew that travels perpendicular to the main spindle axis, this permits facing operations to be performed. This leadscrew can be engaged with the feedscrew (mentioned previously) to provide automated movement to the cross-slide, only one direction can be engaged at a time as an interlock mechanism will shut out the second gear train.
Compound rest
(2) The compound rest (or top slide) is the part of the machine where the tool post is mounted. It provides a smaller amount of movement along its axis via another leadscrew. The compound rest axis can be adjusted independently of the carriage or cross-slide. It is utilized when turning tapers, when screwcutting or to obtain finer feeds than the leadscrew normally permits.
The slide rest can be traced to the fifteenth century, and in the eighteenth century it was used on French ornamental turning lathes. The suite of gun boring mills at Woolwich Arsenal in the 1780s by the Verbruggan family also had slide rests. See also Woolwich Arsenal railway station, Arsenal FC The Royal Arsenal, Woolwich, originally known as the Woolwich Warren The story has long circulated that Henry Maudslay invented it, but he did not (and never claimed so). Henry Maudslay ( August 22, 1771 – February 14 1831) was a British Machine tool innovator Tool and die maker The legend that Maudslay invented the slide rest originated with James Nasmyth, who wrote ambiguously about it in his Remarks on the Introduction of the Slide Principle, 1841; later writers misunderstood, and propagated the error. This article is about the Scottish Engineer. For the Inventor of Basketball, see James Naismith. Maudslay did help to disseminate the idea widely. It is highly probable that he saw it when he was working at the Arsenal as a boy. In 1794, whilst he was working for Joseph Bramah, he made one, and when he had his own workshop used it extensively in the lathes he made and sold there. Joseph Bramah ( 13 April 1748 – 9 December 1814) born Stainborough Lane Farm Wentworth, Yorkshire, England Coupled with the network of engineers he trained, this ensured the slide rest became widely known and copied by other lathe makers, and so diffused throughout British engineering workshops. A practical and versatile screw-cutting lathe incorporating the trio of leadscrew, change gears, and slide rest was Maudslay's most important achievement. A screw-cutting lathe is a machine (specifically a Lathe) capable of cutting very accurate Screw threads via single-point screw-cutting (which is the process of precisely
The first fully documented, all-metal slide rest lathe was invented by Jacques de Vaucanson around 1751. Jacques de Vaucanson ( February 24, 1709 – November 21, 1782) was a French inventor and artist with a mechanical background who is credited Year 1751 ( MDCCLI) was a Common year starting on Friday (link will display the full calendar of the Gregorian calendar (or a It was described in the Encyclopédie a long time before Maudslay invented and perfected his version. Encyclopédie ou dictionnaire raisonné des sciences des arts et des métiers (Encyclopedia or a systematic dictionary of the sciences arts and crafts was a general It is likely that Maudslay was not aware of Vaucanson's work, since his first versions of the slide rest had many errors which were not present in the Vaucanson lathe.
Toolpost
(1) The tool bit is mounted in the toolpost which may be of the American lantern style, traditional 4 sided square style, or in a quick change style such as the multifix arrangement pictured. The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, Shapers and planers. The advantage of a quick change set-up is to allow an unlimited number of tools to be used (up to the number of holders available) rather than being limited to 1 tool with the lantern style, or 3 to 4 tools with the 4 sided type. Interchangeable tool holders allow the all the tools to be preset to a center height that will not change, even if the holder is removed from the machine.
Tailstock
The tailstock is a toolholder directly mounted on the spindle axis, opposite the headstock. The spindle (T5) does not rotate but does travel longitudinally under the action of a leadscrew and handwheel (T1). The spindle includes a taper to hold drill bits, centers and other tooling. A machine taper is a system for securing cutting bits and other accessories to a machine tool's powered rotating spindle For the ficitonal character see Drill Bit (Transformers. Drill bits are cutting tools used to create cylindrical holes A lathe center (or center) is a tool that has been ground to an included angle of 60 ° and is used to accurately position a workpiece about its axis A chuck is a specialised type of clamp used to hold rotating tools or materials The tailstock can be positioned along the bed and clamped (T6) in position as required. There is also provision to offset the tailstock (T4) from the spindles axis, this is useful for turning small tapers.
The image shows a reduction gear box (T2) between the handwheel and spindle, this is a feature found only in the larger center lathes, where large drills may necessitate the extra leverage.
Types of metal lathes
There are many variants of lathes within the metalworking field. Metalworking is craft and practice of working with Metals to create individual parts assemblies or large scale structures Some variations are not all that obvious, and others are more a niche area. For example, a centering lathe is a dual head machine where the work remains fixed and the heads move towards the workpiece and machine a center drill hole into each end. The resulting workpiece may then be used "between centers" in another operation. The usage of the term metal lathe may also be considered somewhat outdated these days, plastics and other composite materials are in wide use and with appropriate modifications, the same principles and techniques may be applied to their machining as that used for metal.
Center lathe / engine lathe / bench lathe
The terms center lathe, engine lathe, and bench lathe all refer to a basic type of lathe that may be considered the archetypical class of metalworking lathe most often used by the general machinist or machining hobbyist. A machinist is a person who uses Machine tools to make or modify parts primarily Metal parts a process known as Machining. Conventional Machining, one of the most important material removal methods is a collection of material-working processes in which power-driven Machine tools, such as lathes The name bench lathe implies a version of this class small enough to be mounted on a workbench (but still full-featured, and larger than mini-lathes or micro-lathes). The construction of a center lathe is detailed above, but depending on the year of manufacture, size, price range, or desired features, even these lathes can vary widely between models.
Engine lathe is the name applied to a traditional late-19th-century or 20th-century lathe. It is assumed that the word engine was added to the description to separate them from foot-powered and hand-powered lathes. The word engine would refer to a steam engine, which was the standard industrial power source for many years. A steam engine is a Heat engine that performs Mechanical work using Steam as its Working fluid. The works would have one large steam engine which would provide power to all the machines via a line shaft system of belts. The line shaft was the Power transmission system at the heart of the Industrial Revolution. Therefore early engine lathes were generally 'cone heads', in that the spindle usually had attached to it a multi-step pulley called a cone pulley designed to accept a flat belt. Different spindle speeds could be obtained by moving the flat belt to different steps on the cone pulley. Cone-head lathes usually had a countershaft (layshaft) on the back side of the cone which could be engaged to provide a lower set of speeds than was obtainable by direct belt drive. These gears were called back gears. Larger lathes sometimes had two-speed back gears which could be shifted to provide a still lower set of speeds.
When electric motors started to become common in the early 20th century, many cone-head lathes were converted to electric power. At the same time the state of the art in gear and bearing practice was advancing to the point that manufacturers began to make fully geared headstocks, using gearboxes analogous to automobile transmissions to obtain various spindle speeds and feed rates while transmitting the higher amounts of power needed to take full advantage of high speed steel tools. This is the page for mechanical Gears For other uses see Gear (disambiguation For the gear-like device used to drive a roller chain see Sprocket A bearing is a device to permit constrained relative motion between two parts typically rotation or linear movement In Physics, power (symbol P) is the rate at which work is performed or energy is transmitted or the amount of energy required or expended for High speed steel (often abbreviated HSS, sometimes HS) is a material usually used in the manufacture of machine Tool bits and other cutters
The inexpensive availability of electronics has again changed the way speed control may be applied by allowing continuously variable motor speed from the maximum down to almost zero RPM. (This had been tried in the late 19th century but was not found satisfactory at the time. Subsequent improvements have made it viable again. )
Toolroom lathe
A toolroom lathe is a lathe optimized for toolroom work. The word toolroom (less often styled tool-room or tool room) has three related senses It is essentially just a top-of-the-line center lathe, with all of the best optional features that may be omitted from less expensive models, such as a collet closer, taper attachment, and others. There has also been an implication over the years of selective assembly and extra fitting, with every care taken in the building of a toolroom model to make it the smoothest-running, most-accurate version of the machine that can be built. However, within one brand, the quality difference between a regular model and its corresponding toolroom model depends on the builder and in some cases has been partly marketing psychology. For name-brand machine tool builders who made only high-quality tools, there wasn't necessarily any lack of quality in the base-model product for the "luxury model" to improve upon. In other cases, especially when comparing different brands, the quality differential between (1) an entry-level center lathe built to compete on price, and (2) a toolroom lathe meant to compete only on quality and not on price, can be objectively demonstrated by measuring TIR, vibration, etc. In any case, because of their fully-ticked-off option list and (real or implied) higher quality, toolroom lathes are more expensive than entry-level center lathes.
Turret lathe and capstan lathe
Turret lathes and capstan lathes are members of a class of lathes that is used for repetitive production of duplicate parts (which by the nature of their cutting process are usually interchangeable). The turret lathe is a form of metalworking lathe that is used for repetitive production of duplicate parts (which by the nature of their cutting process are usually interchangeable The turret lathe is a form of metalworking lathe that is used for repetitive production of duplicate parts (which by the nature of their cutting process are usually interchangeable Interchangeable parts are components of any device designed to specifications which insure that they will fit within any device of the same type It evolved from earlier lathes with the addition of the turret, which is an indexable toolholder that allows multiple cutting operations to be performed, each with a different cutting tool, in easy, rapid succession, with no need for the operator to perform setup tasks in between (such as installing or uninstalling tools) nor to control the toolpath. Indexing in reference to motion is moving (or being moved into a new position or location quickly and easily but also precisely (The latter is due to the toolpath's being controlled by the machine, either in jig-like fashion [via the mechanical limits placed on it by the turret's slide and stops] or via IT-directed servomechanisms [on CNC lathes]. A jig is any of a large class of tools in Woodworking, Metalworking, and some other crafts that help to control the location or motion (or both of a tool Information technology ( IT) as defined by the Information Technology Association of America (ITAA is "the study design development implementation support The abbreviation CNC stands for computer numerical control, and refers specifically to a computer "controller" that reads G-code )
There is a tremendous variety of turret lathe and capstan lathe designs, reflecting the variety of work that they do.
Gang-tool lathe
A gang-tool lathe is one that has a row of tools set up on its cross-slide, which is long and flat and is similar to a milling machine table. The idea is essentially the same as with turret lathes: to set up multiple tools and then easily index between them for each part-cutting cycle. Instead of being rotary like a turret, the indexable tool group is linear.
Multispindle lathe
- See also: screw machine
Multispindle lathes have more than one spindle and automated control (whether via cams or CNC). A screw machine is a metalworking machine used in the high volume manufacture of turned components A cam is a projecting part of a rotating Wheel or shaft that strikes a Lever at one or more points on its circular path The abbreviation CNC stands for computer numerical control, and refers specifically to a computer "controller" that reads G-code They are production machines specializing in high-volume production. The smaller types are usually called screw machines, while the larger variants are usually called automatic chucking machines, automatic chuckers, or simply chuckers. A screw machine is a metalworking machine used in the high volume manufacture of turned components Screw machines usually work from bar stock, while chuckers automatically chuck up individual blanks from a magazine. Typical minimum profitable production lot size on a screw machine is in the thousands of parts due to the large setup time. Once set up, a screw machine can rapidly and efficiently produce thousands of parts on a continuous basis with high accuracy, low cycle time, and very little human intervention. (The latter two points drive down the unit cost per interchangeable part much lower than could be achieved without these machines. )
Rotary transfer machines might also be included under the category of multispindle lathes, although they defy traditional classification. They are large, expensive, modular machine tools with many CNC axes that combine the capabilities of lathes, milling machines, and pallet changers.
CNC lathe / CNC turning center
CNC lathes are rapidly replacing the older production lathes (multispindle, etc) due to their ease of setting and operation. A milling machine is a Machine tool used for the shaping of Metal and other Solid Materials. The abbreviation CNC stands for computer numerical control, and refers specifically to a computer "controller" that reads G-code They are designed to use modern carbide tooling and fully utilize modern processes. Tungsten carbide, WC, or tungsten semicarbide, W2C, is a chemical compound containing Tungsten and Carbon, similar The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, Shapers and planers. The part may be designed by the Computer-aided manufacturing (CAM) process, the resulting file uploaded to the machine, and once set and trialled the machine will continue to turn out parts under the occasional supervision of an operator. Computer-aided manufacturing ( CAM) is the use of computer-based software tools that assist engineers and machinists in manufacturing or prototyping product components The machine is controlled electronically via a computer menu style interface, the program may be modified and displayed at the machine, along with a simulated view of the process. The setter/operator needs a high level of skill to perform the process, however the knowledge base is broader compared to the older production machines where intimate knowledge of each machine was considered essential. These machines are often set and operated by the same person, where the operator will supervise a small number of machines (cell).
The design of a CNC lathe has evolved yet again however the basic principles and parts are still recognizable, the turret holds the tools and indexes them as needed. The machines are often totally enclosed, due in large part to Occupational health and safety (OH&S) issues. Occupational safety and health is a cross-disciplinary area concerned with protecting the Safety, Health and welfare of people engaged in
With the advent of cheap computers, free operating systems such as Linux, and open source CNC software, the entry price of CNC machines has plummeted. Linux (commonly pronounced ˈlɪnəks Open source is a development methodology which offers practical accessibility to a product's source (goods and knowledge For example, Sherline makes a desktop CNC lathe that is affordable by hobbyists.
Swiss-style lathe / Swiss turning center
For work requiring extreme accuracy (sometimes holding tolerances as small as a few tenths of a thousandth of an inch), a Swiss-style lathe is often used. A Swiss-style lathe holds the workpiece with both a collet and a guide bushing. The collet sits behind the guide bushing, and the tools sit in front of the guide bushing, holding stationary on the Z axis. To cut lengthwise along the part, the tools will move in and the material itself will move back and forth along the Z axis. This allows all the work to be done on the material near the guide bushing where it's more rigid, making them ideal for working on slender workpieces as the part is held firmly with little chance of deflection or vibration occurring.
This style of lathe is also available with CNC controllers to further increase its versatility.
Most CNC Swiss-style lathes today utilize two spindles. The main spindle is used with the guide bushing for the main machining operations. The secondary spindle is located behind the part, aligned on the Z axis. In simple operation it picks up the part as it is cut off (aka parted off) and accepts it for second operations, then ejects it into a bin, eliminating the need to have an operator manually change each part, as is often the case with standard CNC turning centers. This makes them very efficient, as these machines are capable of fast cycle times, producing simple parts in one cycle (i. e. no need for a second machine to finish the part with second operations), in as little as 10-15 seconds. This makes them ideal for large production runs of small-diameter parts.
Combination lathe / 3-in-1 machine
A combination lathe, often known as a 3-in-1 machine, introduces drilling or milling operations into the design of the lathe. These machines have a milling column rising up above the lathe bed, and they utilize the carriage and topslide as the X and Y axes for the milling column. The 3-in-1 name comes from the idea of having a lathe, milling machine, and drill press all in one affordable machine tool. These are exclusive to the hobbyist and MRO markets, as they inevitably involve compromises in size, features, rigidity, and precision in order to remain affordable. Maintenance repair and operations or maintenance repair and overhaul (MRO is fixing any sort of mechanical or Electrical device should it Nevertheless, they meet the demand of their niche quite well, and are not incapable of high accuracy given enough time and skill. They may be found in smaller, non-machine-oriented businesses where the occasional small part must be machined, especially where the exacting tolerances of expensive toolroom machines, besides being unaffordable, would be overkill for the application anyway from an engineering perspective.
Mini-lathe and micro-lathe
Mini-lathes and micro-lathes are miniature versions of a general-purpose center lathe (engine lathe). A micro lathe (also styled micro-lathe or microlathe) is a Machine tool used for the complex shaping of Metal and other Solid They typically have swings in the range of 3" to 7" (70 mm to 170 mm) diameter (in other words, 1. 5" to 3. 5" (30 mm to 80 mm) radius). They are small and affordable lathes for the home workshop or MRO shop. The same advantages and disadvantages apply to these machines as explained earlier regarding 3-in-1 machines.
As found elsewhere in English-language orthography, there is variation in the styling of the prefixes in these machines' names. They are alternately styled as mini lathe, minilathe, and mini-lathe and as micro lathe, microlathe, and micro-lathe.
Wheel lathe
A lathe for turning the wheels of railway locomotives and rolling stock [1]
References
External links
General education on lathes and their use
- Lathes.co.uk - Everything you ever wanted to know about lathes
- Introduction to Metal Spinning on Manual and Automatic CNC Lathes
- South Bend diagrams and description of the 9 inch Workshop Lathes. A locomotive is a railway Vehicle that provides the motive power for a Train. Rolling Stock was a Newspaper of ideas and a chronicle of the 1980s published in Boulder, Colorado
History of the lathe
- Medieval and Renaissance lathes
- The development of the lathe
- Early Wood-Working
- Spring pole lathe
- On ye art and mystery of Turning
- Modern Machine Shop Practice a historic Victorian text describing lathe design, construction and use in 1880s.
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