Turning, drilling and boring machines

The engine lathe is the oldest and most common turning machine. It is used for shaping the external surface of a cylindrical part by rotating the work-piece against a cutting tool. The turret lathe carries a number of cutting tools that can be used in sequence to shape, drill, bore, ream, and cut threads on both exterior and interior cylindrical surfaces. A fully automatic turning machine can feed in the work-piece and perform all cutting operations. A duplicating lathe can replicate quantities of an identical shape by using a tracing mecha­nism and a template.

The drill press, the most common form of drilling machine, is essentially one or more rotating drill heads mounted in the tool holder, which can be moved against the work-piece. Similar machines perform such operations as boring, finishing a drilled hole with a rotat­ing, single-edged cutting tool; reaming (which is a boring operation performed to very high tolerances); and tapping, cutting an interior screw thread. Many drilling operations can be done with the turret lathe. Special boring mills bore holes in work-pieces that are too large to fit a lathe.

Words and word combinations

in sequence – по черзі

replicate - копіювати

EXERCISES

I. Give the Ukrainian equivalents:

1.	the engine lathe
2.	a turning machine
3.	shaping
4.	an external surface
5.	rotating
6.	a work-piece
7.	a cutting tool
8.	the turret lathe
9.	to drill
10.	to bore
11.	to ream
12.	to cut threads
13.	to feed in
14.	a duplicating lathe
15.	a tracing mecha­nism
16.	a template
17.	the drill press
18.	finishing
19.	a single-edged cutting tool
20.	tapping
21.	an interior screw thread
22.	a boring mills

II. Give the English equivalents.

1) токарний верстат......................................................

2) фасонування зовнішніх та внутрішніх поверхонь...........................................................................................................................................................

3) нарізання різьби.........................................................................................................................

4) свердління...................................................................................................................................

5) розточка....................................................................................................................................

6) розшивка.....................................................................................................................................

7) вироби,ідентичні за формою.....................................................................................................

8) шаблон........................................................................................................................................

9) шляхом обробки заготів різцем................................................................................................

III. Speak about machine tools according to the plan.

1. What machine tool is it?

2. What is it used for?

3. What is the principle of its work?

4. Could you provide some more information about it?

5. In what does it differ from other similar machine tools?

6. Where this machine tool can be used?

7. What are the drawbacks of it?

 

Text 10

THE LATHE

The modern lathe is a development of one of the earliest machine tools. It has played an important part in the growth of modern industry and mass-production. Today lathes can be completely auto­mated, i.e. produced with computer numerical control (CNC), and require minimum attention from their operators.

The engine lathe is the oldest and most common turning machine. It is used for shaping the external surface of a cylindrical part by rotating the workpiece against a cutting tool. The turret lathe carries a number of cutting tools that can be used in sequence to shape, drill, bore, ream, and cut threads on both exterior and interior cylindrical surfaces. A fully automated turning machine can feed in the work-piece and perform all cutting operations. A duplicating lathe can replicate quantities of an identical shape by using a tracing mecha­nism and a template.

Drilling, boring, making threads, knurling and screw-cutting are other operations that can be carried out on this versatile machine, producing work of very high precision.

The basic principle is simple. The work is fixed by some means to a spindle driven by an electric motor. As the metal revolves at speed, cutting tools are brought into contact with it and the waste is cut away. If the tool travels parallel to the spindle axis cylindrical forms are made. If the tool cuts at right angles to the axis, flat surfaces are produced. At any tool position between 0°-90° to the axis, tapers or conical forms result.

 

Words and word combinations

computer numerical control (CNC) –числове програмне управління (ЧПУ)

the engine lathe – фасонний токарний верстат

cutting operations – токарні операції

a template – шаблон

knurling – нанесення насічок

a spindle – шпиндель

0°-90° – from zero to ninety degrees

EXERCISES