THE DRAFTSMAN'S OUTFIT 2. For a beginner to do good work, reliable tools are necessary. It is worth while to pay a little more money at the outset in order to have an equipment which will give satisfactory service. Perhaps nothing is more disheartening to a beginner than to have his best efforts meet with little success, on account of poor instru ments. For mechanical drafting, the articles in most common use constituting the draftsman's outfit are the following: Set of instruments.
Paper and tracing cloth.
Sandpaper or fine file.
Besides these, there are many others which are used at times, especially by the professional draftsman—such as the protractor, erasing shield, burnisher, proportional dividers, section liner, beam compasses, steel straight-edge, pantograph, brushes, etc.
3. The set of drawing instruments is the item of greatest cost, and should be selected very carefully. A good set purchased from some reliable house, will, with proper care, do good service for years. These sets are sold in various ways—some being put up in a leather case with a stiff cover; others, adapted especially for car rying in the pocket, being in a case with a limp cover and folding flaps. The various pieces may also be bought separately, if desired.
4. Figs. 1 and 2 show a set of instruments in two kinds of cases, Fig. 2 being the folding pocket style. In Figs. 3 to 10 the different instruments are shown separately.
5. Fig. 3 is the compass. One leg carries lead, the other a needle-point. Each leg is jointed, and the lower half of one leg is detach able at the joint. This is to provide for inserting the compass pen or the lengthening bar.
6. The lengthening bar, Fig. 4, is to enable the draftsman to draw pencil or ink circles larger than can be drawn with the ordinary compass. When the pencil leg is detached from the compass, the lengthener is inserted in its place, and the pencil leg or the compass pen fastened in its end.
7. The compass pen, Fig. 5, is for inking circles or circular arcs, and is inserted in the compass in place of the pencil leg.
8. The dividers are shown in Fig. 6; and the small dividers or bow spacers in
9. The bow pencil or small compass and the bow pen are shown in Figs. S and 9 respectively.
10. The ruling pen, Fig. 10, is specially de signed for ruling straight lines, the ordinary writing pen being wholly unsuitable.
11. The beam compass is shown in Fig. 11. This instrument is for accurately laying off dis tances, and for drawing circles which are beyond the capacity of the ordinary dividers or com passes. It consists essentially of the beam (not shown in the drawing), a thin straight bar of hardwood, and two pieces which slide along the bar and which may be clamped to it at any de sired distance apart. These sliding attachments are called channels, and carry one the needle point, and the other the pencil or pen as desired. As shown at the right, there is a micrometer screw for obtaining great precision in setting the compass for any given distance or radius.
12. The protractor is shown in Fig. 12. This instrument, while not in such constant use as some of the others, is nevertheless necessary at times. It is made of various substances, such as metal, celluloid, cardboard, etc., and is used for laying out angles which cannot be obtained with the triangles and which cannot be easily constructed geometrically. The graduations represent degrees or subdivisions; and the center of the graduated circle is marked by a scratch or small notch on the line through the two zero points. A line drawn from the center of the circle through any point of division—as, for example, through 70—will make an angle of 70 degrees with the zero line of the protractor. Other angles may be drawn in a similar way.
13. The drawing board, shown in Fig. 13, is used to supply a smooth, even surface on which to fasten the drawing paper. It should be made of straight-grained, well-seasoned soft wood; and the cleats at the ends of the board should have straight edges. Some cheap drawing boards have a strip of brass or steel screwed on at one end; these, however, are likely to warp, and are not to be recommended. The board should not be allowed to remain in the sun or near heating apparatus.