- •Chapter II mechanical tools
- •I. Translate the following words and phrases from the text:
- •VII. Translate the following sentences, observing different meanings of the words and word combinations given in italics:
- •VIII. Make up questions to which the italicized words are the answers:
- •IX. Using the following words and word combinations describe the drawing shown in Fig. 2:
- •I. Translate the following words and phrases from the text:
- •II. Supply the missing words:
- •III. Translate the following sentences into English using the infinitive instead of the attributive clauses:
- •IV. Make up questions to which the italicized words are the answers:
- •V. Giving the answers to the following questions describe the principle of operation of pliers, bench-shears, and alligator shears and pipe-cutter shown in Figs 4, 5, 7, and 8:
- •I. Translate the following words and phrases from the text:
- •VI. Make up questions to which the italicized words are the answers:
- •VII. Giving answers to the following questions describe Fig. 9:
- •I. Translate the following words and phrases from the text:
- •VII. Translate the following sentences into English:
- •II. Translate the following groups of words, paying attention to the meaning of suffixes:
- •III. Supply synonyms for the following words:
- •V. Translate the following sentences observing different meanings of the words in italics:
- •VI. (a) Translate the following text using a dictionary:
- •VII. Using the following words and word combinations describe the principle of operation of the vernier calipers shown in Fig. 13:
- •VIII. Giving answers to the following questions describe the principle of operation of the micrometer shown in Fig. 14:
- •IX. Describe the measuring tools shown in Figs 15, 16, and 18.
- •6. Machine-cutting tools
- •II. Use these verbs in the past participle form and make up word-combinations using past participles as attributes:
- •III. Underline the suffixes and prefixes and translate into Russian the following group of words of the same stem:
- •IV. Choose synonymical groups out of the following list:
- •V. Change the following sentences, using the subordinate clause instead of participle phrases. Translate the sentences into Russian:
- •VI. Translate the following sentences into Russian:
- •VII. Translate the following sentences into English using different ways of expressing obligation:
- •VIII. Give different meanings of the words, give some examples of their use.
- •IX. Make up questions to which the italicized words are the answers:
- •X. (a) Read and translate the following text without using a dictionary:
- •7. Drills and rilling
- •I. Translate the following words and phrases from the text:
- •II. Retell the text giving answers to the following questions:
- •III. Form adverbs from the following adjectives:
- •IV. Underline the suffixes and prefixes and translate into Russian the following groups of words of the same stem:
- •V. Supply the missing words:
- •VI. Connect the following sentences using the conjunction either... Or:
- •VII. Translate the following sentences into English using the past participle instead of the attributive clauses:
- •VIII. Analyse and translate the following sentences:
- •IX. Describe Fig. 22 orally using the following words and word combinations:
- •8. Threading tools
- •I. Translate the following words and phrases from the text:
- •II. Retell the text giving answers to the following questions:
- •III. Supply synonyms for the following words:
- •I. Translate the following words and phrases from the text:
- •VII. Connect the following sentences using participle constructions and translate the sentences into Russian:
- •VIII. Giving answers to the following questions describe the construction and principle of operation of the centre shown in Fig. 26:
- •IX. Describe the construction of the running centre shown in Fig. 27.
- •10. Holding work in a chuck
- •I. Translate the following words and phrases from the text:
- •VII. Giving answers to the following questions describe the jaw chuck shown in Fig. 28 and its principle of operation:
- •VIII. Using the following words and word combinations describe the construction and principle of operation of the concentric chuck shown in Fig. 29:
- •IX. Describe the construction and principle of operation of the contracting chuck shown in Fig. 30.
- •11. Holding work in a vice
- •I. Translate the following words and phrases from the text:
- •VI. Translate into English:
- •VII. (a) Read and translate the text without using a dictionary:
- •VII. Using the following words and word combinations describe the principle of operation of the swivel vices shown in Fig. 31:
7. Drills and rilling
Drilling is one of the cutting operations producing cylindrical holes of different diameter in solid material by means of rotating tools called "drills" (Fig. 22).
The most common type of drill in use1 is the twist drill made of a tempered steel round bar stock. Twist drills are made with two, three, or four spiral grooves or flutes milled from the solid. These grooves or flutes winding around the body of the drill serve for forming the cutting edges of the drill, as well as for removing the chips formed in drilling from the hole.
Straight-Shank Drill
Tapered-Shank Drill
Fig. 22. Drills
The twist drill comprises three principal parts: body, shank and point. The twist drill has two cutting edges known as the "lips". These cutting edges, or lips, are connected by a third edge, called a "web". It is this part that gives rigidity and strength to the drill. When in use the first two cutting edges remove the material from the work, while the third one penetrates into the material by rubbing rather than cutting.
In order to drill holes in a metal the cutting edges of a drill should be correctly ground to a certain angle. When a drill is ground correctly, its cutting edges, or lips, should have equal length whereupon each of them should make the same angle with the centre line. Otherwise the drill will make holes the diameter of which is larger than that of the drill. This may disable the drill and cause an undesirable waste of material. Drills have shanks of various types, the most commonly used being those having straight and tapered shanks. The shank of the drill serves for clamping the drill either in the chuck spindle or socket of a drilling machine. The above part of the drill may be either of a cylindrical shape, like in2 straight-shank drills, or of tapered shape in tapered-shank drills
The third part of the drill is called a "drill point". It is always ground to a cutting angle varying with the kind of material to be drilled. For hard materials this cutting angle equals 140° and for soft materials it equals 90°. The cutting edges of flat drills used for drilling holes in steel or in cast-iron are ground to an angle of 100° to 120°. All the drills get worn while drilling and they should be re-ground from time to time.
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1. The most common type of drill in use — самым обычным используемым типом сверла...
2. like in — как в, подобно
Exercises
I. Translate the following words and phrases from the text:
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. Which is the most widely used tool for drilling? 3. What purposes do twist drill flutes serve? 4. What are the principal parts of a twist drill? 5. What are the cutting edges of a twist drill called? 6. What part of the twist drill gives it rigidity and strength? 7. Why should the cutting edges of a drill be correctly ground and have equal length? 8. What purposes does the shank of the drill serve? 9. What are the cutting angles of a drill point for hard and soft materials?