Переведите текст. C h i p p i n g M e t a l a n d Ch i p p i n g T o o l s

 

C h i p p i n g M e t a l a n d Ch i p p i n g T o o l s

Chipping is a process of removing metal from a work piece 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 remover from a work piece; this process is very labor-consuming and is applied only in cases when the work piece 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 on a bench vice. The work piece to be tooled is fixed during the cutting process in the bench vise.

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 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. The plan AO 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 ABO 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”. They 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 forger tool carbon steel, their weight depending on the stock to be removed.

Используйте следующие слова и выражения в собственных предложениях.

To chip, chisel, stock, mechanical tools, blade, wedge, edge, cutting, angle, acute angle, clearance angle, cape chisel, front rake, to strike, to forge, solid

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1. What is chipping? 2. What instruments are used in chipping? 3. What is a chisel? What types of chisels do you know? 4. What does the work of a chisel depend on? 5. What does the angle of the cutting edge of a chisel depend on? 6. Why is the top face of a chisel given a certain slope? 7. What is the front race? 8. What plane is called the “front cutting face”? 9. What plane is called the “back cutting face”? 10. What is the clearance angle, the lip angle and the cutting angle?

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1.Chisels are used … removing stock … works. 2. Chisels are usually made … a high grade steel. 3. The cutting edge … a chisel is … a chisel depends … the strength … a stock to be chipped. 5. Stock are chipped … means … a chisel and a hammer.