- •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:
III. Supply synonyms for the following words:
to perform, female thread, male thread, construction, instrument, form
IV. Give derivatives from the following words and translate them into Russian:
to operate, to perform, to cut, to construct, to thread, to tap, to fasten, usual, to hold
V. Supply antonyms for the following words:
straight grooves, manual tapping, final, to coincide
VI. Translate the following sentences observing different meanings of the word machine:
1. This machine is mainly used for removing large pieces of metal. 2, The engineer explained in his lecture how to machine workpieces of different shapes and sizes. 3. The size and shape of all machine parts should be checked by means of different measuring tools.
VII. Make up questions to which the italicized words are the answers:
1. With mechanical tapping in cast iron, bronze, brass, copper, and aluminium one tap is used. 2. When steel is tapped a set of two tools is used. 3. Before cutting threads the tap should be firmly set in a tap wrench. 4. A threading die is made of internally threaded flat steel stock.
VIII. Describe Figs 23 and 24 orally using the following words and word-combinations:
the tap, to be made, a cylindrical bar stock, to consist, the working part, the shank, to be used, fastening the threading tool, in a chuck or in a tap wrench, two or three taps, to be applied, manual tapping, the first and the second taps, to serve, to cut threads, the third tap, final thread cutting
IX. Giving answers to the following questions describe the threading die shown in Fig. 25:
1. What operations are performed with a threading die? 2. What material is a threading die made of? 3. How is a threading die threaded? 4. What is there between the cutting grooves of a threading die?
9. METHODS OF HOLDING WORKS BETWEEN CENTRES
When machining a piece of work on a lathe the former is usually mounted between the lathe centres. Having been mounted on the lathe the work is supported by the conical points of the live and dead centres. The work must therefore have centre holes in each end drilled by using a combined drill and a countersink. The size of the centre hole has to be proportioned to the weight of the work and the size of cut to be taken. By virtue of the clearance holes the work does not rest on the extreme points of the centres. This is important because otherwise the position of the work will be indefinite. Owing to this method of holding work between centres, the work can be removed from the lathe as often as may be desired. If the work has to be mounted again between centres for further treatment, it will rotate about the same axis as before.
The two lathe centres are mounted in two spindles: one — the live centre is held in the headstock spindle and turns together with the spindle and the work, the other— the dead centre is held in the tailstock spindle and in most cases does not turn and rubs against the work piece. The point of the dead centre should be hardened to prevent its wearing during the operations performed on the lathe. Both lathe centres should always be aligned, i. e. the points are to meet when the tailstock with its centre is moved up to the headstock centre. A turner tests the alignment of the centres by taking a cut and then measuring both ends of the cut by a micrometer. Having got the same measurements, the turner may be sure that the centres are aligned and he may proceed with the turning. The centre shown in Fig. 26 consists of a cone, on which the work to be treated is installed, and of a tapered shank, which fits corresponding taper holes in the headstock spindle and tailstock poppet.
Fig. 26. Centre:
1 — cone; 2 — tapered shank
When works are machined at high speeds or when the former are too heavy a dead centre and the work will be heated up so as to cause excessive wear from friction. In such cases the so called "running centres" are used. Fig. 27 shows a running centre inserted into the taper hole of the tailstock poppet. The centre rotates on ball bearings. The thrust exerted on the centre is taken by the available ball thrust bearing. The tapered shank fits the taper hole of the tailstock poppet.
Fig. 27. Running Centre:
1 — centre; 2, 4 — ball bearings; 3 — tapered shank; 5 — ball thrust bearing
Exercises