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There are many different categories of lathes. Some of the major categories are listed below.
Woodworking Lathes: Woodworking lathes are the oldest variety. 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. With wood, it is common practice to press and slide sandpaper against the still-spinning object after shaping to smooth the surface made with the metal shaping tools.
Metalworking Lathes: In a metalworking lathe, metal is removed from the workpiece using a hardened cutting tool, which is usually fixed to a solid moveable mounting, either a toolpost or a turret, which is then moved against the workpiece using hand-wheels and/or computer controlled motors. These (cutting) tools come in a wide range of sizes and shapes depending upon their application.
Cue Lathes: Cue lathes function similar to turning and spinning lathes allowing for a perfectly radially-symmetrical cut for billiard cues. They can also be used to refinish cues that have been worn over the years.
Glassworking Lathes: Glassworking lathes are similar in design to other lathes, but differ markedly in how the workpiece is modified. Glassworking 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 malleable, and subject to forming either by inflation (“glassblowing”), or by deformation with a heat resistant tool. Such lathes usually have two headstocks 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.
Metal Spinning 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. 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).
Ornamental turning Lathes: 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 frames, eccentric chuck and elliptical chuck, solids of extraordinary complexity may be produced by various generative procedures.
Reducing Lathe: A reducing lathe is a specialized lathe that is designed with this feature, and which 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.
Rotary Lathes: A lathe in which softwood, like spruce or pine, or hardwood, like birch, logs are turned against a very sharp blade and peeled off in one continuous or semi-continuous roll.
Watchmaker’s Lathe: Watchmakers lathes are delicate but precise metalworking lathes, usually without provision for screw-cutting, and are still used by horologists for work such as the turning of balance shafts. A handheld tool called a graver is often used in preference to a slide mounted tool.
The design of lathes can vary greatly depending on the intended application; however, basic features are common to most types. These machines consist of (at the least) a headstock, spindle, bed, carriage, and tailstock. Better machines are solidly constructed with broad bearing surfaces for stability, and manufactured with great precision.
Headstock: 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. The headstock consist of the headstock, Speed change Mechanism, House of the main spindle, and change gears.
Spindle: A spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically to refer the entire rotary unit, including not only the shaft itself, but its bearings and anything attached to it.
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. There are different types of Bed: Inverted V beds, flat beds, combination of inverted V and flat beds.
Carriage: The carriage holds the tool bit and moves it longitudinally (turning) or perpendicularly (facing) under the control of the operator. The operator moves the carriage manually via the hand-wheel or automatically by engaging the feed shaft with the carriage feed mechanism. This provides some relief for the operator as the movement of the carriage becomes power assisted. The hand-wheels on the carriage and its related slides are usually calibrated, both for ease of use and to assist in making reproducible cuts. The carriage typically comprises a top casting, known as the saddle and the side casting, known as the apron.
Tailstock: The tailstock also known as a footstock, is a device often used as part of an engineering lathe wood-turning lathe, or used in conjunction with a rotary table on a milling machine. The tailstock is a tool holder directly mounted on the spindle axis, opposite the headstock. The spindle does not rotate but does travel longitudinally under the action of a lead-screw and hand-wheel. The spindle includes a taper to hold drill bits, centers and other tooling. The tailstock can be positioned along the bed and clamped in position as required. There is also a provision to offset the tailstock from the spindle axis; this is useful for turning small tapers.
A lathe is a machine tool which rotates the work piece on an axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation. Lathes are usually used in woodturning, metalworking, metal spinning, and glass working. A metal lathe or metalworking lathe is a large class of lathes designed for precisely machining relatively hard materials.
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. In machining terminology, where the larger context is already understood, they are usually called lathes, or else referred to by more specific subtypes names such as tool-room lathe, turret lathes, etc. These rigid machine tools remove materials from a rotating workpiece via typically linear movements of various cutting tools such as tool bit and drill bits.
Most suitable equipped metalworking lathes can also be used to produce most solids of revolution, plane surface and screw threads or helices. Ornamental lathes can produce three-dimensional solids of incredible complexity. The material can be held in place by either one of two centers, at least one of which can be moved horizontally to accommodate varying material lengths. Other work holding methods include clamping the work about the axis of rotation using a chuck or faceplate using clamps.
When a workpiece is fixed between the headstock and the tailstock, it is said to be “between centers”. When a workpiece is supported at both ends, it is more stable, and more force may be applied to the workpiece at a right angle to the axis of rotation, without fear that the workpiece may break loose. 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 in this manner, less force may be applied to the workpiece, in case the workpiece rip free. Thus, most work must be done axially, towards the headstock, or at the right angles, but gently.
When a workpiece is mounted with a certain axis or rotation, worked, then remounted with a new axis or rotation, this is referred to as “eccentric turning” or “multi axis turning”. The result is that various cross sections of the workpiece are rationally symmetric, but the workpiece as a whole is not rationally symmetric.
[Antonb] added 10-bit encoding to a standard servo. He’s removed the potentiometer, separated its shaft and used it to rotate a small magnet. By sandwiching an AS5040 rotatory encoder IC into the servo’s housing he can now measure the precise orientation of the servo horn. This is made easier by his tiny breakout board for the chip. If you want to layout your own PCB you can download the EagleCAD files for this device. Take a look at the final product in the clip after the break.