The equipment of a machine shop naturally depends upon the size and variety of work it has to do. There are different sizes of machines of the same kind for machining different sizes of castings and forgings, also there are different kinds of machines for doing the same kind of work in different grades of refinement. An economic consideration is to have as few machines as possible to do as great a range of work as possible, and this is best accomplished by choosing high-grade machines which are not only adapted to variety of work, but are also able to stand the durable test of producing good work in minimum time. Fig. 151 shows the general arrangement of a large machine shop.

Fig. 151. - Machine-Shop Interior.

The metal-cutting machines of a machine shop are known as machine tools and the work done by them is known as machining. The principal equipment of the machine shop is as follows:

(1) Several types of machine tools, and their cutting tools.

(2) Vise benches equipped with suitable vises for hand work and tools for chipping, filing, scraping, hand-thread cutting, etc.

(3) Small tools for measuring, trying, adjusting, etc.

(4) A laying-off table, also called a marking-off table for laying out and marking work preparatory to machining it.

(5) Portable tools worked by hand or driven by compressed air or electric power.

(6) Crane and other appliances for lifting and transporting heavy work.

(7) A tool room where all tools are kept when not in use.