The Model Locomotive Engineer, Fireman, and Engine Boy

This historic book may have numerous typos or missing text. Not indexed. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1879. Not illustrated. Excerpt: ... the third side, describe an arc cutting the former at c. 3. Join A c and B C. The triangle is thus completed as required. To draw a straight line, so as to form any required angle with another straight line. 1. Let B A c, Fig. 44, be the given angle, and r E the z line upon which an equal angle is to be drawn at the point D. From the points A and D, with any convenient radius, describe arcs F G and H I. Fis-44' 2. Set off the length ot the arc F G, contained between the lines A B and A c, upon the arc H I, and draw D I. The angle E D I will be equal to the given angle B A C. Longitudinal sectional elevations (or objects cut through lengthways vertically), longitudinal sectional plans (or objects cut through lengthways horizontally), and transverse sections (or objects cut through across vertically), are necessary drawings at all times, and to get measurements from the actual engine to make such drawings is often an impossibility, however essential it is to show internal arrangements, often made in the casting of a piece of machinery, and never seen again unless broken up. There is often no other way of showing the thickness of material than a section. If the object in question is in process of construction in the factory, the only resort for what is required for the purpose is the large original working drawings which show the structure of the interior parts. In drawings of machinery it is usual to place the plan above the side elevation, and central on the paper if possible. End elevations or sections should be to the right and left of the principal elevation, and adjoining the end of the elevation which they severally represent. When only one view of a steam-engine has to be made, the side elevation (or view showing the crank breadth) is the most likely ...