Fig. 147.
A most convenient—and except for its extreme lightness, which is not good in a drawing stand—a most admirable device is shown in [fig. 138]. The drawing table is simply a drawing board with folding legs; these are made from hard-wood, while the top is made of soft, seasoned pine, with square corners; while the device is strong and well braced, it can be folded and easily carried about—all as shown in the illustration.
Fig. 148.
THE TEE-SQUARE.
This is an instrument in the form of a letter T, as shown in the [figures 149 and 150]; the two parts are known as stock and blade; the horizontal part of the letter (T) is the stock, and the vertical part the blade—hence the name, T-square; to form the square, the two parts are joined together in such a way as to make them exactly at right angles to each other; the stock, which is applied to the working edge of the drawing board, being about one-third the length of the blade, and about three times its thickness.
Figs. 149 and 150.
To be perfect in construction, a tee-square should be as light as is consistent with its necessary strength and stiffness of parts; it should be made of suitable material easily manufactured, put together, and repaired, and withal as truly correct as is possible to be made. Such a square is represented in [fig. 148]; it has a taper blade, which is generally about double the width where secured to the stock as it is at the end.
