Ex.25. Explain the difference between the shaper and the planer.

Ex.26. Prove the advanteges of the automatic lathe.

Supplementary reading

Text for written translation with a dictionary.

Read the text and translate them in writing. Use a dictionary.

Major categories of lathes

Text D Woodworking lathes

A modern woodworking lathe.

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

There are also woodworking lathes for making bowls and plates, which have no horizontal metal rail, as the bowl or plate needs only to be held by one side from a metal face plate. Without this rail, there is very little restriction to the width of the piece being turned.

Text E Metalworking lathes

In a metal working 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.

The toolpost is operated by leadscrews that can accurately position the tool in a variety of planes. 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. Cutting Quid 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 computer for mass production of parts.

Metalworking lathes are commonly provided with a variable ratio gear train to drive the main leadscrew. This enables different pitches of threads to be cut. 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.

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 B A), while one with an imperial leadscrew will readily cut imperial unit based threads such as BSW or UTS (UNF,UNC).

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. A chuck has movable jaws that can grip the workpiece securely.

Text F 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.

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 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 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.

Text G 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). 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). 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.

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.

Text H Ornamental turning lathes

The ornamental turning lathe was developed around the same time as the industrial screwcutting 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. 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.

Text I Reducing Lathe

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 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 (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 master die.

 

Unit 11

Drilling machines

I. Language.

Ex.1 Remember the following words and word combinations:

drilling machine -свердлильний верстат - сверлильний станок

reaming -розгортання, зенкування (отворів) -развертывания, зенкование (отверстий)

lapping -нахльостування - нахлёстка, притирка

countersinking -зенкування - зенкование

upright spindle machine -вертикально свердлильний верстат - вертикально сверлильний станок

multiple spindle machine -багатошпиндельний верстат - многошпиндельный станок

radial spindle machine -радіально-свердлильний верстат - радиально-сверлильний станок

guill -втулка, порожнистий вал - полый вал, втулка

column -опорна стойка, колона - опорная стойка, колонна

gearbox -коробка швидкостей - коробка скоростей

gearing -зубчаста передача - зубчатая передача

adjustment -регулювання - регулировка

crank - кривошип - кривошип

to equip - обладнувати - оборудовать

ratchet lever - храповий важіль - храповый рычаг

heavy machine duty -верстат для важких робіт - станок для тяжёлых работ

plain machine -простий фрезерувальний верстат - простой фрезерный станок

sensitive machine - свердлильний верстат підвищеної точност -сверлильный станок повышенной точности

delicate works -крихкі заготовки - хрупкие заготовки

simultaneous -одночасний - одновремённый

drive -привід, приводити до руху - привод, приводить в движение

worm gear -черв’ячна передача - червячная передача

radial arm -радіальна траверса - радиальная траверса

to require -вимагати - требовать

push-button - кнопочне управління - кнопочное управление

 

Ex.2 Read the international words and guess their meaning:

Operation, class, type, represent, variety, spindle, axially, adapt, range, vertical, construction, classify, delicate, radial, horizontal, position.

Ex.3 Make up words using these suffixes and translate them:

1) -ment; 2) -tion; 3) -aus; 4) -able.

a) to construct

b) to employ
c) to adjust
d) to revolve

e) to vary

f) to equip

g) to operate

Ex.4 Translate the following word combinations:

A great variety of operations, the necessary feed for the drill, at a proper speed, at any point, for lighter work, a number of movable drills, the fully automatic machine, any desired position.

Ex.5 Find the meaning of the following polysemantic words. Translate the sentences:

1. Since

1. Welding has been known since ancient times. 2. Mercury cannot be welded since it has a low melting temperature. 3. Since we are going to read English and American magazines we should have some idea of main technological processes.

2. Rate

1. The rate of flow under the bridge was rather high. 2. The rate of population growth is increasing. 3. This is a first-rate drilling machine.

3. Push

1. He gave the door a hard push and entered the house. 2. “Don’t push me, or I’ll face down“, said the boy. 3. He pushed his way through the crowd. 4. This machine requires only push-button operations.

 

 

II. Reading