II. Holding work in a vice

Vices are attachments which are mainly used for holding workpieces in machine and fitting shops. It should be noticed that a vice may also be used as an attachment for holding workpieces on a metal-cutting lathe.

Depending on the character of operation performed bench vices or parallel vices may be applied. Bench vices are made from forged steel and are of rugged construction. If their construction were not rugged, they could not be used when heavy-duty operations such as cutting, riveting, etc. are performed. A bench vice consists of two jaws: the movable jaw and the solid jaw. At the end of the solid jaw there is a lug for securing the vice to a bench. The extension rod of the jaw is built-in a wooden pillow. When a workpiece is clamped between the jaws they are moved together by means of a square-threaded screw. By unscrewing the screw the jaws are moved apart by a spring riveted to the solid jaw. In parallel vices the jaws move parallel to each other. It should be pointed out that parallel vices in their turn are subdivided into swivel vices and plain vices.

Fig. 31. Swivel Vice:

a - front view; b - cross-sectional view:, 1 - vice base*;- 2 - solid jaw; 3 - movable jaw;

4 - screw; 5 - fixed nut; 6 - handle; 7 - swivel plate; 8 - spindle; 9 - bolt; 10 - lever

A swivel vice (Fig. 31), being the most convenient vice in operation, consists of a vice base*, a solid jaw and a movable jaw. The motion of die movable jaw is provided by the rotation of a screw inserted into a fixed nut. When the screw is rotated by means of a handle the former will screw in and move the movable jaw to the workpiece to he clamped. The vice base is mounted on a swivel plate being connected with the latter by a spindle. A bolt is inserted into a T-groove. By turning a handle the bolt may be loosened and the vice may be turned in a desired direction.

Plain vices differ entirely from swivel vices in the absence of the swivel plate and that the vice base is bolted directly to a bench. The vice of such a type is made from grey iron, steel hardened plates with a nut being screwed to its jaws. Parallel vices are convenient for clamping workpieces., but as their jaws are of little strength they are non-suitable for heavy-duty operations.

* American - vice ground

Exercises

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

vices, attachment, bench vice, to rivet, rugged, parallel vices, heavy-duty operation, to secure, movable jaw, solid jaw, lug, pillow, extension rod, swivel vices, plain vices, front view, cross-sectional view, fixed nut, to loosen

II. Answer the following questions:

1. What are vices and what purposes are they used for? 2. On what lathes are vices used? 3. Depending on what features may bench or parallel vices be applied for holding workpieces? 4. What material are vices made of? 5. If the construction of the vices were not rugged, could they be used for heavy-duty operations? 6. What main parts does a bench vice consist of? 7. Why is the end of the solid jaw of the bench vice provided with a lug?

III. Find in the text English equivalents of:

тиски, вид спереди, проекция поворотных тисков в попе речном разрезе, поворотная плита, пружина, основание, завинчивать, неповоротные тиски, тавровый или Т-образный паз, закрепленная гайка, поворачивать, обеспечивать, приспособление

IV. Underline the suffixes and prefixes and translate into Russian the following words:

attachment, mainly, operation, movable, wooden, convenient, unscrew, disconnect, extension, rugged, performed

V. Translate the following sentences, paying attention to different meanings of should and would:

1. It is necessary that all fitting shops should be supplied with bench vices. 2. If the jaws of parallel vices had not been of low strength, the parallel vices would have found greater application in industry. 3. It is very important that workpieces being in the process should be firmly clamped in vices. 4. If fitting shops were not supplied with vices, how would workers clamp workpieces? 5. It is necessary that the vice should be fastened to a bench. 6. Great attention should be paid to the proper securing of the vice to the bench. 7. Providing all the requirements were met, the efficiency of the swivel vices would be increased. 8. If the bolt had been loosened enough, we should have been able to turn the swivel vices in a desired direction.

VI. Translate into English:

1 .Следовало бы отметить, что неподвижные тиски не очень удобны для работы. 2. Важно, чтобы к губкам тисков привинчивали стальные закаленные пластинки. 3. Необходимо., чтобы на пластинках, привинчиваемых к губкам, была насечка. 4. Следовало бы указать, что параллельные тиски имеют существенный недостаток, заключающийся в малой прочности их губок. 5. Если бы губки параллельных тисков были более прочными, тиски могли бы использоваться для закрепления тяжелых деталей. 6. Если бы крепление стуловых тисков на верстаке обеспечивало надежность их установки, они двигались бы во время работы.

VII. (a) Read and translate the text without using a dictionary:

Vices are used in tool-rooms and as attachments on metal-cutting lathes for holding workpieces. Vices of rugged construction can hold heavy work, easily withstanding the most severs duty imposed on them. There are different types of vices such as plain vices and swivel vices. The jaws of all the vices are made of accurately ground tool steel. They may be moved together or apart by means of a handle. The plain vice is used for light milling operations and is fastened to the bench by means of a screw. The swivel vice may be turned through any angle as the base of the vice is held to the table with a swivel plate. Universal vice may

be used for general tool-room work. It can be swiveled up to 90° in the vertical plane and up to 360° in the horizontal plane.

(b) Answer the following questions:

1. Where are vices widely used? 2. What do they serve for? 3. What types of vices do you know? 4. What is the difference between plain and swivel vices? 5. By what means are the jaws of all vices moved together or apart? 6. What may the universal vice be used for?

VII. Using the following words and word combinations describe the principle of, operation of the swivel vices shown in Fig. 81:

a swivel vice, to be the most convenient vice, to consist, a base, a solid jaw, a movable jaw, the motion, the movable jaw, to be provided, the rotation, a screw inserted, a fixed nut, the screw, to be rotated, a handle, the vice base, to be mounted, a swivel plate, by means of a spindle, to loosen, the bolt, the vice, to be turned in any direction