B) Compound conjunctions

Союзами называются служебные слова, которые употребляются для соединения членов предложения и частей предложения. Среди них выделяется группа составных или парных союзов: both … and … – как … так и …; as well as – также … как и …; а также …; either … or – или … или …; либо … либо …; whether …or … – ли … или …; neither … nor … – ни … ни … .

Sample: Angle grinders may be used both for removing excess material off a piece or simply cutting into a piece. – Заточенные под углом шлифовальные диски могут использоваться как для удаления лишнего материала с заготовки, так и простого ее разрезания.

Angle grinders are widely used in metalworking and construction, as well as in emergency rescue. – Заточенные под углом шлифовальные диски используются в металлообработке и строительстве, а также в спасательных работах.

Text

Read the text describing the design of the lathes and remember the names or their parts in English

The Structure of Lathes

Metalworking lathes were originally designed for precisely machining relatively hard materials – metals. However, with the advent of plastics and other materials, and with their inherent versatility, the lathes are used in a wide range of applications, and a broad range of materials. These rigid machine tools remove material from a rotating workpiece via the movements of various cutting tools, such as tool bits and drill bits. These machines consist, mainly, of a headstock, bed, carriage, tailstock and work-and-tool holder.

The headstock houses the main spindle, speed change mechanism and change gears. The headstock is required to be made as robust as possible due to the cutting forces involved. The main spindle is generally hollow to allow long bars to extend through to the work area. The spindle then runs in bearings and is fitted with holding devices such as chucks or faceplates. This end of the spindle will also have an included taper, usually Morse, to allow the insertion of tapers and centers.

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.

The feedscrew is a long driveshaft that allows a series of gears to drive the carriage mechanisms. Both the feedscrew and leadscrew are driven by either the change gears or an intermediate gearbox known as a quick change gearbox or Norton gearbox. These intermediate gears allow the correct ratio and direction to be set for cutting threads or worm gears.

The carriage holds the tool bit and moves it longitudinally (turning) or perpendicularly (facing) under the control of the operator.

The compound rest is the part of the machine where the tool post in mounted. The compound rest axis can be adjusted independently of the carriage or cross-slide. It is utilized when turning tapers, to control depth of cut when screwcutting or precision facing, or to obtain finer feeds (under manual control) than the feed shaft permits.

The toolpost is the device into which the tool bit is mounted. Toolposts may be of different styles. Interchangeable tool holders allow all the tools to be preset to a center height that will not change.

The tailstock is a toolholder directly mounted on the spindle axis, opposite the headstock. 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 are many variants of lathes within the metalworking field. It should be noted that nowadays the same principles and techniques used for metals may be applied for machining plastics and other composite materials. To variants of metal lathes, for example, belong centering lathes and engine lathes. A centering lathe is a dual head machine where the work remains fixed and the heads move towards the workpiece and machine a centre drill hole each end. Engine lathe is the lathe with automatic feed to the cutting tool. The word «engine» is used here in the meaning of mechanical device, opposed to the lathes with manual feed. It is worth mentioning that all these lathes are being rapidly replaced by CNC lathes.

Exercise 1. Translate the word combinations with Participle I in the function of adverbial modifier of time:

when turning tapes, when screw-cutting, when precision facing.

Exercise 2. Use the verbs in brackets in the proper Tense form:

1. Firstly metalworking lathes (to design) for machining hard materials.

2. Nowadays, the lathes (to use) in a wide range of application.

3. As a rule, machine-tools (to remove) material from a rotating workpiece.

4. Machine tools (to consist) of numerous parts.

5. The headstock (to house) a spindle and change gears.

6. The spindle (to run) in bearings and (to be fitted) with holding device.

7. The feedscrew (to allow) gears to drive the carriage mechanisms.

8. Intermediate gears (to allow) the correct direction for cutting threads.

9. The carriage (to hold) the tool bit and (to move) it longitudinally or perpendicularly.

10. The word «engine» (to be used) in the meaning of mechanical device.

Exercise 3. Complete the sentences with the proper words corresponding to Russian in brackets:

1. Metalworking lathes were designed for (точной обработки) hard materials.

2. Machine-tools remove materials (с вращающейся заготовки).

3. (Передняя бабка) houses the main spindle and (механизм переключения скоростей).

4. The headstock must be made as (прочной) as possible.

5. The main spindle is usually (полый).

6. (Шпиндель) is fitted with (патроном или планшайбой).

7. One end of the spindle has an included (конус).

8. (Суппорт) and (задняя бабка) are to be aligned parallel with (осью) of the spindle.

9. (Направляющие параллели) restrain (суппорт) and (заднюю бабку) in (направляющем устройстве).

10. (Резцедержатель) is the device into which (вставной резец) is mounted.

Exercise 4. Find English equivalent to Russian word:

1. суппорт а) compound rest c) support

b) carriage d) bed;

2. присущий, a) described c) necessary

свойственный b) inherent d) needed;

3. станина (станка) a) machine c) track

b) carriage d) support;

4. малое зубчатое а) pinion c) rack

колесо b) gear d) pitch;

5. патрон а) toolpost; c) faceplate;

b) feedscrew; d) chuck;

6. направляющие a) set track c) ways

параллели b) faceplate d) carriage;

7. резцедержатель a) cross-slide c) spindle

b) chuck d) toolpost;

8. сменная шестерня a) intermediate gear c) change gear

b) leadscrew d) pitch.

Exercise 5. Translate into English:

1. Металлорежущие станки были созданы для обработки твердых материалов.

2. С появлением пластмасс станки стали использоваться в более широком диапазоне.

3. Станки снимают материал с заготовки с помощью режущих инструментов.

4. Режущим инструментом может быть резец, фреза или шлифовальный диск.

5. Основными узлами станков являются станина, суппорт, передняя и задняя бабка, держатель заготовки и инструмента.

6. Суппорт передвигается с помощью зубчатой рейки и зубчатого колеса.

7. Суппорт удерживает вставной резец и передвигает его продольно или перпендикулярно.

8. Сложный суппорт – это часть станка, на которой устанавливается резцедержатель.

9. Задняя бабка устанавливается вдоль станины и закрепляется в нужном положении.

10. За последнее время все станки заменяются станками с числовым управлением.

Speaking:

Exercise 6. Give the summary of the text, using key vocabulary and tell about:

1. the purpose of designing machine-tools;

2. the cutting tools used in machine-tools;

3. the basic parts of machine-tools;

4. moving parts of machine-tools;

5. immovable parts of machine-tools;

6. the varieties of lathes;

Checklist for Section VI:

1. How is Participle I in the functions of adverbial modifier of time translated into Russian?

2. What is the role of compound conjunctions?

3. What is the function of machine-tools in mechanical engineering?

4. What are the basic parts and units of machine-tools?

Section VII

Technological Processes of Metal Hot Treatment

Grammar: Participle II in the function of an attribute.

Word-formation: suffixes –ity (-ty).

Speaking: The Essence of Metal Hot Treatment.

Practise the reading of the words:

manufacture	[/mænju:′fæktə]
temperature	[′temprItə]
chemical	[′kemIkəl]
thermal	[′θə:məl]
medium	[′mI:dIəm]
ancient	[′eInənt]
technique	[tek′nI:k]
further	[′fə:ðə]
require	[rI′kwaIə]
since	[sIns]
Fahrenheit	[′fɑ:rInhaIt]
Celsius	[′selsIəs]
vital	[′vaItl]