- •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:
Chapter II mechanical tools
CHIPPING METAL AND CHIPPING TOOLS
Chipping is a process of removing metal from a workpiece by means of a cutting instrument such as a chisel and a hammer. This process is used when a large piece of metal has to be removed from a workpiece; this process is very labour-consuming1 and is applied only in cases when the workpiece cannot be machined. Chipping is used in cases when it is necessary to cut off a piece of metal from sheet metal. Chipping of large parts is always done on an anvil but very often it is done in a bench vice. The workpiece to be tooled is fixed during the cutting process in the bench vice.
There are different tools used in metal-working shops for chipping stocks such as chisels. A chisel is a tool made of very hard steel, having a cutting edge at one end of the blade. This cutting edge is wedge-shaped. Under the effect of an external force applied to the wedge it cuts into the metal. The work of the wedge depends mainly on its cutting angle. The cutting edge of the chisel should be sharpened to an acute angle so as to provide for the best cutting ability, depending on the stock to be chipped. The harder the metal, the larger should be the cutting
angle of the chisel and vice versa. An angle of about 70° is suitable for most work. Fig. 2 shows a scheme of the process of cutting into metal, and the angles of the wedge.
Fig. 2.
a — bar with an obtuse
angle; b — bar with an acute angle
Fig. 3. Process of Chipping by Means of a Chisel:
1 — front cutting face; 2 — front rake; 3 — cutting angle; 4 — back cutting face; 5 — clearance angle; 6 — lip angle
Fig. 3 shows the process of chipping by means of a chisel, as well as the cutting angles. The plane АО called the "front cutting face" or the "top face" is given a backward and sidewise slope for sliding the chips off the tool in a convenient direction while the plane OB is called the "back cutting face". Being formed between the front and back cutting faces of the chisel the angle AOB is known as the lip angle. The angle BOC is the clearance angle which is formed by the back cutting face of the chisel and the surface of the work to be treated. The slope in the direction of the chisel length in which the chip moves is called the "front rake" or "true rake". The angle AOC formed by the lip angle and clearance angle is known as the "cutting angle". There are different types of chisels such as flat chisels, cape chisels, etc.
Hammers are striking tools used in chipping, bending and other operations. Hammers are made of a solid piece of forged tool carbon, steel, their weight depending on the stock to be removed.
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1. labour-consuming - трудоемкий
Exercises
I. Translate the following words and phrases from the text:
to chip, chisel, stock, mechanical tolls, blade, wedge, edge, cutting angle, acute angle, plane, lip angle, clearance angle, cape chisel, front rake, to strike, to forge, solid
II. Retell the text giving answers to the following questions:
1. What is chipping? 2. What is a chisel? What types of chisels do you know? 3. What does the work of a chisel depend on? 4. What does the angle of the cutting edge of a chisel depend on? 5. Why is the top face of a chisel given a certain slope? 6. What is the front rake? 7. What plane is called the "front cutting face? 8. What plane is called the "back cutting face? 9. What is the clearance angle? 10. What is the lip angle? 11. What is the cutting angle?
III. Fill in the blanks with prepositions by, from, in, of, on:
1. Chisels are used … removing stock … works. 2. Chisels are usually made … a high grade steel. 3. The cutting edge … a chisel is ... the form … a wedge. 4. The correct cutting angle … a chisel depends … the strength … a stock to be chipped. 5. Stocks are chipped ... means … a chisel and a hammer.
IV. Supply antonyms for the following words:
hard, large, suitable, convenient, backward, long
V. Make up adverbs from the following words and translate them into Russian:
different, hard, main, external, large, convenient
VI. Change the following sentences using the Infinitive Construction and translate them into Russian:
Example: The chisels which are to be used for chipping metals are made of high
grade steel.
The chisels to be used for chipping metals are made of high grade steel.
1. Different types of chisels are made of a good grade chisel steel which has to be forged, annealed, and then hardened and tempered. 2. Chisels which must be applied for chipping metal stocks are made of hard steel. 3. Working a metal to a desired shape by forging produces the best combination of physical characteristics for parts which will be highly stressed. 4. An auxiliary equipment which will be used together with the forging hammer must withstand the vibration or impact of the forging blows. 5. The weight of hammers depends on the stock which will be removed. 6. The work required to separate the chip from the stock will depend upon the material which is to be machined and the separation area.