bringing a second square close up to another edge, as shown at b. The first square may then be moved up or down as required, as shown in dotted lines, when the other two edges will be constantly parallel to their original positions. A more extended range of movement may be obtained by using the edge of the T-square as a guide on which to move the set square to its successive positions, as indicated at c and d, where the full lines represent those to be drawn.
The T-square, especially when polished, has an annoying habit of slipping off the sloping board. This may be checked by passing a small rubber band—such as is used for fastening rolls of paper - -around the blade near the stock.
Sharpening Pencils.—This should be done neatly and carefully with a sharp penknife or chisel; good work can never be done with a Hunt or irregularly sharpened pencil. For ruling straight lines a chisel-shaped " point " or edge is advocated by some, similar to b and c, adjacent Fig. For freehand work, setting off lengths, or for use with French curves, a long conical point should be used as shown at a.
" h Use the -hencil lightlv. Do not " en-
Pencils grave the paper, nothing looks worse
(a) Conical Point 011 a drawing than a network of white
(b) and (r) Chisel marks or furrows that once contained pencil lines. It would be a counsel of perfection to advise that no false lines should be drawn. These may be looked upon as inevitable with a beginner, but. he need not draw undue attention to his errors or tentative attempts.
When a drawing is to be finished in pencil, the preliminary construction may be made with a hard pencil, which will make a faint line, easily removable. After the drawing is complete and found to be correct, remove superfluous ends to the lines, with the rubber, and go carefully over the
METHOD OF INKING DRAWINGS 27
entire drawing with a softer pencil. This operation is called " Jining-in "
Inking-in.—If the drawing is to be finished in ink. it is advisable to draw every line first in pencil, and to carry the ends beyond their intersections, as otherwise it is difficult to see where to stop the pen when the ruler lies over the lines. After the inking-in is finished the pencil lines can be removed with soft rubber or bread crumbs.
The method of holding a ruling pen when inking a line is illustrated here. It is, of course, held in the right hand, with the pen upright or nearly so, and the forefinger resting upon the setting screw. The precise height of the hold is, of course, a matter of taste, and is also dependent upon the length of the pen. The pen should have the ink rising about in. between the nib, which must be. screwed up until the desired gauge of line is obtained. This should be tried on a spare piece of paper—not the margin of your drawing- and once the pen is set, it should not be altered until all the lines of that depth are finished. Hold the rule or straight edge (which should have a slight under bevel, as shown, to prevent the ink adhering and causing a blot), firmly, with lingers spread out; this latter seems such an obvious precaution as to be needless to mention, but for the fact that the author has sometimes spoiled a drawing himself by neglecting it. When the draughtsman is intent upon drawing his line correctly, lie is apt to relax the pressure with the left hand, then disaster follows swiftly. Curved lines other than circular are best inked in by the aid of French curves, as shown in Fig. 1, p. 28, where the grained portion indicates one end of a " curve," placed so as to coincide with the portion of the line between a and b, the dotted line indicating the curve reversed to mark in from c-d. The connection b~c is made at a third adjust-
38 WHERE TO COMMENCE
ment, and a fourth adjustment enables the part d e to be drawn, the fully inked line, a-b-c~d-e, representing the finished line obtained.
In joining circular to straight lines it is better to draw the circular ones first, and connect the straight ones to them exactly at the springing points as shown at B, Fig. 2, on this page. This avoids the unsightly breaks in the continuity of the lines shown at A, Fig. 2, in which the straight lines were drawn first.
When removing pencil lines, rub in the direction of the cn
Fig. 2. Right and Wrong methods of joining Straight to Curved Lines lines, not across them, and clean the rubber of lead, on a piece of coarse linen, frequently.
Keeping the Drawing Clean.— Beginners always have a difficulty with this. The soiled appearance of their pencilled drawings is due to the squares taking up a little of the blacklead when passing over the lines and depositing it where it is not wanted. To prevent this, wipe them occasionally with a piece of linen and, when lining-in, pass a clean sheet of paper (tissue or tracing paper is best, as it can be seen through) over the parts finished, so that the hand or instruments shall not cause smudging.
Where to Commence a Drawing. -This depends some ■ what on the nature of the drawing. When making a number of simple exercises or small separate drawings, commence
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