Working Drawings

Working drawings are those from which objects can be constructed. They are also, and properly, called mechanical drawings, industrial drawings and construction drawings. They are necessary to guide the workman in nearly every branch of industry.

A working drawing is made of two or more geometric views of the object. A geometric drawing shows an object in its simplest form; that is, having length or width, or showing but one face of the object. This can be represented on a flat surface by one drawing; then another must be made to represent the face, showing the thickness of the solid, and so on, until as many views have been made as there are dissimilar faces.

The Real Shape of the Surface cannot always be shown in these drawings, but simply the contour or outline when the surface is curved or oblique. The real shape, however, is readily understood by the position of the several views and the lines connecting them.

When we know that certain angles and edges come in contact, we are enabled to understand the form that will result. Certain conventional lines are used in working drawings, and the knowledge of their use is necessary.

List of the Lines and Explanations – Dotted lines connect different parts of different views that are in contact in the object.

Dot-and-dash lines are center lines, sometimes called construction lines. They are used when the object has a curved surface or is difficult to illustrate.

Dash lines represent invisible edges. Complete lines represent visible edges of surfaces.

In making working drawings the top view is usually placed directly over or under the front view, with corresponding points opposite. When more than two views are necessary, the side views are placed beside the front or upright, with the corresponding points exactly opposite.

Exercises in the Three Dimensions Dimensions of a Line, which is known by its length.

Show, in a drawing, the length of a line twelve inches long, drawn to the scale of three inches to the foot (J=I); that is to say, each actual foot to be represented by three inches on the drawing, and every actual inch by a quarter of an inch on the drawing.

Dimensions of a Surface, which are known by its length
and breadth.

Show, in a drawing, the length and breadth of a sheet of paper twelve inches long and six inches wide; i. e., 12″x6″. Scale, three inches to the foot; i. e., 3″=1′.

Dimensions of a Solid, the longest dimension being known by its length. the next longest by its breadth, while its shortest is known by its thickness.

Show, in a drawing, the length, breadth and thickness of a
board 12×6. Scale, 3″=1′.

Exercises in Working Drawings – Make working drawings of simple articles of furniture, like tables, chairs, bookshelves, etc. The measurements and views should be so plain that a workman would form a clear idea of the article and be able to construct one from the drawing.