Test 1. Machine - Tools

Machine-tools are machines designed for cutting metal parts by means of a cutting tool. The machine-toe comprises the principle manufacturing equipment in a machine shop. It is the original source of ever manufactured article we use or touch. It can not only reproduce itself but it is the only machine which can create other machines.

Without a machine-tool the engineer would be stripped of his power and opportunities. Every tool, machine and material stems directly from machine-tools or was evolved from machines which themselves were produced by machine-tools.

Machining operations, or metal-cutting processes, lie at the basis of all modern industrial production.

The general term «machine-tool» is applied to various classes of power-driven metal-cutting machine employed in the machine shop for the purpose of shaping many commercial products.

The function of machine-tools is to hold both the work and a cutting tool or tools and move them relative t each other to obtain the proper cutting action and at an economic speed.

The part of the machine-tool which removes the metal during a metal-cutting process is called a cutting too Cutting tools used for various metal-cutting operations may be different and the type depends on the work whicр is performed and on the material. The main types of machine-tools used for industrial production are lathes drilling machines, milling machines, etc.

The lathe is a machine-tool in which work is held so that it can be rotated about an axis. The cutting tool i traversed past the work from one end to the other. It is designed primarily for turning and boring operations However, in addition to turning and boring, many other operations may also be performed on a lathe. The lathe i considered to be the oldest but still the most important of all machine-tools. Any shop, containing machines с machine-tools, contains a lathe.

Lathes used in shop practice can be of different designs and sizes. These lathes fall into various types, either according to their characteristic constructional features, or according to the work for which they are designed.