CHAPTER IX.—MODEL STEAM-ENGINES, AND HOW TO MAKE THEM.
By Paul N. Hasluck, Author of Lathe-work, &c.
I.—Principles of the Steam-Engine.
This chapter is intended to fully describe the constructive details of miniature steam-engines. It is proposed to first give an idea of the general principles which govern steam-engines, and to explain the various characteristics and methods of constructing different types of engines. The boiler and its several fittings and attachments will be duly described, and then minute directions given for constructing engines with oscillating and slide-valve cylinders. Illustrations of both vertical and horizontal engines will be given, and also sketches in all cases where they will serve to explain more fully the meaning of the text.
This is a brief outline of the scope of the present chapter. Those readers who have acquired only slight manual dexterity in the use of tools will find little difficulty in making the engines illustrated, if the instructions given are carefully followed. In each case the minute details of the various processes incidental to our engineering work will be carefully described, so that those unacquainted with the mechanical arts will be able to comprehend the method of procedure.
Model engines, in every stage of manufacture, from the rough castings direct from the foundry to the complete, highly-finished working model, may now be purchased in nearly every town of importance throughout Great Britain. Though this trade is of but recent growth, its continual extension proves that model engines are objects of interest to a large number of the rising generation, and hence it is felt that information as to their manufacture will prove acceptable to very many readers.
It will be advisable to gain an insight into the principles which govern the action of a steam-engine, and to learn some of the technical peculiarities, before proceeding to attempt its manufacture. There are numerous text-books on the steam-engine, which may be studied with advantage, and which show the theoretical principles.
The modern engine, which now claims our attention, is the result of numerous successive improvements. The application of steam as a motive power was probably originally made by Hero, who, 150 B.C., constructed, or at least described, an Æolipile. This was a hollow sphere with hollow bent arms attached; when water placed inside the sphere was heated, and steam generated, it issued from the arms, and reacting on the air caused the sphere to rotate. A model of this, the primogenitor of the modern steam-engine, can be bought at many opticians’ shops for about one shilling.