VI. Translate the following sentences into Russian:

1. The distance that the tool is set into the work for cutting operations is referred to as the depth of cut. 2. Metals may be so strong that it is difficult to produce a tool capable of cutting off the chip without frequent failures. 3. If the metal to be cut is soft, the top rake of the tool is decreased. 4. When a tool cuts metal a force is exerted on its face by the material pushed ahead, and a friction force is set up along the face of the tool by a sliding chip. 5. If the tool were not ground correctly, it would not cut freely. 6. The basic principle of design employed in making single-point cutting tools is the wedge which can be modified in accordance with requirements.

VII. Translate the following sentences into English using different ways of expressing obligation:

1. Все резцы, в зависимости от типа машины, на которой они используются, нужно подразделять на токарные, фрезерные, строгальные и другие. 2. Для того чтобы продлить работу режущего инструмента, следует правильно выбирать скорость резания. 3. Угол заточки инструмента должен меняться в зависимости от материала обрабаты­ваемой детали. 4. Инструмент, который нужно затачивать и устанавливать в определенное положение в автоматическом станке, следует насаживать с меньшей силой, чем обдирочный резец. 5. Режущие инструменты могут затачи­ваться до тех пор, пока не останется маленькая полоска режущей кромки, и все же их можно еще использовать для резки материала.

VIII. Give different meanings of the words, give some examples of their use.

proper, to make, one, for, above, more, that.

IX. Make up questions to which the italicized words are the answers:

1. On solid tools it is necessary to grind the top rake in the tool. 2. To turn cast-iron it is necessary to set the tool above centre. 3. The tool is ground with the slide clearance to prevent the dragging of the tool on the shoulder formed by the cut. 4. If the surface of the work being machined is too great, the cutting edge will be worn too rapidly. 5. Rough­ing tools are applied for roughing or removing excessive metal from the work. 6. To prevent the breakage of the cutting edge of a necking tool, the height of the head is made several times larger than the width of the cutting edge.

X. (a) Read and translate the following text without using a dictionary:

Lathe tools are made of carbon steel, high speed steel and alloys such as stellite and cemented carbide. The stellite and cemented carbide tools are becoming more generally used as their cost is reduced. There are but few carbon steel tools used,¹ the general practice is to use high-speed tool bits in holders. One should determine the kind of tool to be ground, as carbon and high-speed steel require differ­ent treatment. Tools should be marked to show the kind of material from which they are made. To ensure the proper operation of a lathe the cutting tools should be ground by hand or machine. In machine grinding the tool is sup­ported rigidly in a chuck or holder and ground semi-automatically to the desired rake and relief or clearance angles. In grinding by hand, the tool should be supported on the work rest and moved back and forth across the entire face of the grinding wheel. The accuracy of a tool ground by hand depends almost entirely on the skill of the operator.

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1. there are but few carbon steel tools used — применяются лишь немногие резцы из углеродистой стали

(b) Answer the following questions:

1. What steel are lathe tools made of? 2. Why should one determine the kind of tool to be ground? 3. How should the cutting tools be ground to ensure the proper operation of a lathe?

XI. Giving answers to the following questions describe the construction of the cutting tool in Fig. 19 and the an­gles to which a cutting tool shown in Fig. 20 should be ground, and clamping the tool in a tool holder in Fig. 21:

1. What parts does a cutting tool consist of? 2. What is the syno­nym for the word "cutting edge"? 3. By what means can the cutting tip of a tool be ground? 4. What do the shape of a tool as well as its rake and clearance angles depend upon? 5. How can the top rake be varied? 6. What does the top rake depend on? 7. How does the side rake vary for soft material and for steel? 8. What does the front clearance depend on? 9. What action would be performed by the tool if it were ground square without any front clearance? 10. Why is the tool ground with a side clearance? 11. How should the tool be clamped in the tool holder before start­ing the cutting operation?