1. Give the main points of the text, answering the following questions:
What do we call the lathe?
Can it be considered the most important machine tool in a shop?
How is motion transmitted to modern lathes?
Can you give the definition of the swing of a lathe?
Is there only one standard size of lathes?
What types of lathes do you know from the point of view of their design?
What units does the lathe consist of?
2. Choose synonyms out of the following list:
Costly, various, to operate, delicate, commonly, different, capacity, to manipulate, immense, formerly, accurate, to designate, usually, performance, to determine, expensive, huge, previously.
3. Fill in the blanks with the suitable words from the text. The words are given below:
The lathe is probably the most ... tool in the machine shop.
... is transmitted to modern lathes by means of individual motors.
The swing refers to the ... of work that can be rotated on the lathe.
The most common type of lathe is known as an ... ... .
The bench lathe is usually ... for delicate work.
The main casting of the lathe is called the ... .
The headstock carries the lathe ... and ... .
There exist various ... on the lathe to perform functions formerly done on a ... ... .
The ... lathe is similar in ... to an ordinary lathe.
In a lathe the material is ... from the rotating work by the action of the ... ... .
Intended, motion, attachments, removed, special machine, cutting tool, engine lathe, versatile, spindle, gearbox, diameter, tool-room, bed, appearance.
4. Perform the following tasks, basing of the text:
Name the function of the bed, the headstock, the tailstock and the saddle.
Expand oh the following statement:
Modern lathes are highly efficient.
There are many types and sizes of lathes.
5. Characterize lathes according to the following plan:
definition of a lathe
its efficiency
the main parameters of a lathe
types of lathes
main units of a lathe and their functions.
T ext 2
Engine Lathe
This machine is designed for performing a great variety of turning operations under various cutting conditions, including high-speed turning and cutting at heavy stock-removal rates. A wide spectrum of materials can be machined, including tool and heat-resistant steels. The spindle speeds and carriage feeds make it possible to use ceramic and carbide tool, and tools from other superhard materials.
The principal advantages of the 16 K 20 are its powerful drive, the stiffness and strength of its gear trains, resistance to vibration and reliability. The machine is designed for a ten-year service life without an overhaul.
The best features of these machines are the kinematics, the general layout of the principal components, and the arrangement of controls.
The standardized units, namely, the apron and the feed gearbox are manufactured at a specialized factory in Gomel. Their design is well proven, and the components are machined and assembled on a volume-production basis.
Some significant innovations have been introduced in the 16 K 20 lathe, e.g. the non-cutting time has been reduced to a minimum and the machine has become easier to handle.
The four-station tool post ensures a high tool positioning accuracy.
The headstock and the feed gearbox have individual oiling systems. Ample quantities of oil delivered to the shaft, gear wheels, and bearings exclude thermal distortions affecting the accuracy of machining.
The tailstock moves on a compressed-air cushion to reduce wear of the bed ways; the air is mixed with oil to prevent bedway corrosion.
A reliable interlocking system is provided for operator safety. For example, the three jaw chuck is covered with a guard. The lead screw and the feed shaft are covered over the whole length with steel guards. The electric equipment is protected from short circuits by quick-action automatic switches.
EXERCISES