I. Translate the following words and phrases from the text:

bedplate, arm, pitch, bar, lateral, metal cutting tools, pliers, pipe-cutters, hack saw, cutting jaws, to harden, right angle, bench-shears, to press, bed, industrial scrap, groove, to impart, reciprocating motion, to install, fixture, body

II. Supply the missing words:

1. The p… of a blade is the distance from the point of one t… to the point of the next t… .2. This pitch is expressed by the number of t... per one inch of the b… length. 3. The hand hack saw blade is a thin blade with teeth formed on one e… . 4. The flexible h... s... blade is used for s...ing tin, copper, aluminium and other soft metals. 5. Cutting is done by means of different c... t... . 6. For cutting wire such cutting t... as p... are used. 7. One handle of b...-s... is at a r... a... to the other.

III. Translate the following sentences into English using the infinitive instead of the attributive clauses:

Example: Материал, который нужно разрезать, зажимает­ся в тисках.

The metal to be cut is clamped in the vice.

1.Шаг полотна ножовки зависит от материала, кото­рый будет распиливаться, 2. Различные виды стали, ко­торые используются для полотна ножовок, изготовляются на нашем заводе. 3. Полотно ножовки, которое надо ис­пользовать для распиливания этих тонких листов, должно иметь 32 зуба на один дюйм. 4. Труба, которую надо раз­резать труборезом, будет закреплена в специальном при­способлении. 5. При вращении трубореза вокруг изделия, которое надо разрезать, создается режущее усилие.

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

1. This bar is subjected to the action of two sets of exter­nal forces. 2. Cutting is used in cases when it is necessary to separate a piece of metal. 3. Thin wire is cut with pliers. 4. Sheets of metal are cut with bench-shears. 5. Cutting tools are made of carbon steel. 6. Pliers consist of two cutting jaws and two handles.

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:

1. What are pliers used for? 2. What do the pliers con­sist of? 3. What material are bench-shears made of? 4. What are the bench-shears provided with? 5. What purposes are alli­gator shears used for? 6. What principal parts do the alliga­tor shears consist of? 7. What part of the alligator shears is the arm mounted on? 8. Where is the cutting blade of the alligator shears fixed? 9. What motion does the electro­motor impart to the arm and the blade? 10. What purpose are pipe-cutters used for? 11. What parts does a pipe-cutter consist of? 12. Where is the pipe fixed for cutting?

3. FILING AND FILING TOOLS

Filing is the most widely used fitting operation in the practice of metalworking shops used for cutting metal by means of a tool known as a file. By means of a file it is pos­sible to give a different shape and size to a workpiece, to fit one part to another, etc.

The most widely used operations with a file are: (1) fil­ing separate surfaces, (2) filing mating surfaces, (3) filing holes.

A file is a hardened steel bar having a great number of fine cutting edges or teeth running diagonally across its face. These teeth can remove fine chips from a treated work-piece. A file differs from a chisel in having a large number of cutting points instead of one cutting edge and in being driven directly by hand instead of by hammer.

There are various kinds of files applied for finishing different workpieces depending on the shape of their surfaces (Fig. 9).

Flat files are used for filing flat surfaces but the shape of the files is not quite flat because if the file had been made quite flat, it would have prevented the production of a flat surface, as the file would have cut away at the edges of a work and would have left a convex surface.

For filing convex and concave surfaces half-round files are used. A half-round file is made with a convex surface to prevent all the teeth from cutting at the same time, which requires too much pressure on the file, as well as to prevent the file from bending.

Square files are applied for filing square holes and rectangle grooves, while triangular or three-square files are used for filing angles.

Round files are used for filing round holes of small dia­meters, and for filing metal in narrow places diamond-shaped files made of copper strip into which diamond powder has been hammered, or knife files are used.

For filing soft metals rasp files or rasps are employed.

Fig. 9. Files

Exercises