Exercises. I. Use the following words and phrases in sentences of your own:

I. Use the following words and phrases in sentences of your own:

to drill, cylindrical holes, rotating tool, twist drill, flute, to mill, lips, web, spiral grooves, tapered shank, socket

II. Retell the text giving answers to the following questions:

1. What is drilling, and its purpose? 2. By means of what tools is drilling performed? 3. Which is the most widely used tool for drilling? 4. What material is a twist drill made of? 5. What purposes do twist drill flutes serve? 6. What are the principal parts of a twist drill? 7. What are the cutting edges of a twist drill called? 8. What part of the twist drill gives it rigidity and strength? 9. Why should the cutting edges of a drill be correctly ground'? 10. Why should the cutting edges of a drill have an equal length?

III. Form adverbs from the following adjectives:

proper, cylindrical, certain, good, wide, correct, equal

IV. Underline the suffixes and prefixes and translate into Russian the following groups of words of the same stem:

to desire, desirable, undesirable; cylinder, cylindrical, cylindrically; to straighten, straight; to grind, ground, re ground; equal, equality, equalization, to equalize, equalizer, unequal, unequalled

V. Supply the missing words:

1. In drilling h... in metal, heavy pressure must be applied at the drill p.... 2. Spiral f... are found on most drills. 3. The c... angle at the outer corner of the l... should be about 12. 4. The cutting edges of t... d... have angles of top rake and clearance the same as any other с… t... have. 5. The body of metal between the flutes forms what is called the w.... 6. The drills are held in place by their t... shanks or by gripping straight-s... drills in a c...

VI. Connect the following sentences using the con junction either... or:

Example: The body of the twist drill has two spiral grooves. The body of the twist drill has flutes cut on its surface.

The body of the twist drill has either two spiral grooves or flutes cut on its surface.

1. The twist drill is formed by twisting grooves in a fiat piece of steel. The twist drill is formed by milling a cylindrical piece of steel. 2. The grooves serve to form cutting edges of the drill. The grooves serve to remove the chips formed in the process of drilling. 4. The drill flutes serve to lubricate the drill. The drill flutes serve to remove chips from a hole being drilled. 5. The work to be drilled should be clamped in a vice. The work to be drilled should be clamped in a chuck. 6. The web of a drill penetrates into the material being cut. The web of a drill rubs the material.

VII. Translate the following sentences into English using the past participle instead of the attributive clauses:

Example: Часть сверла, которая называется режущей частью, всегда затачивается под определенным углом резания.

The part of the drill called a "drill point" is always ground to a certain cutting angle.

1. Операция, которая выполняется при помощи инструмента, называемого «сверлом», называется «сверлением». 2. Стружки, которые образуются при сверлении, удаляются по канавкам сверла. 3. Режущие кромки сверла, которые используются для сверления, должны затачиваться под определенным углом. 4. Инструмент, который используется для сверления, называется «сверлильным сверлом». 5. Одна из кромок сверла, которая называется «перемычкой», не режет металл.

VIII. Analyze and translate the following sentences:

1. Different kinds of drills are used in drilling, such as: a single-lipped twist drill, normally less than 1" (inch) in diameter. 2. It is formed of a tubular shank which is twisted of seamless tubing to make a single flute. 3. Coolant is carried through the hollow shank, through a small hole in the drill tip, and chips are washed out through the single flute. 4. A four-lipped hollow core drill is designed to carry chips out through a hollow drill shank. 5. This tool is used for enlarging holes and not for drilling solid metal. A two-lipped hollow type deep drill normally is used in drilling solid metal holes ranging from 1" to 3" in diameter and the tip is attached to a tubular steel shank. 7. Coolant carries chips through the flute into the centre of the drill and then out through the hollow shank. 8. Drills of the same design are also used for holes larger than 3". 9. These are provided with replaceable blades in the tip.

IX. Describe Fig. 22 orally using the following words and word combinations:

the body of a twist drill, to represent, a cylindrical rod, to have two spiral grooves, to serve, forming, the cutting edges of the drill, to be called lips, the lips, to be connected, a third edge, to be known., a web, to penetrate into material by rubbing, the shank, the drill, clamping the drill in the chuck, to be of different shapes, cylindrical shanks and tapered shanks, the third part of the drill, a drill point, to be ground to a cutting angle, to depend on, material to be drilled

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