Lucid Arrangement
In geometric and working drawings when plans and sections are incidental to lucid explanation, these latter should appear relatively; that is, the plan should be in alignment with the elevation, etc. Statements and directions as to procedure are often necessary, and these, placed with judgment and in good lettering, are valuable in balancing the drawing. Not that this has any effect on the work, but because it has a good influence on the designer.
Possibly the story of Giotto and the circle that figured in the early school primers is responsible for the very general impression that the use of mechanical instruments is inartistic. Another characteristic of the young beginner is a total disregard for anything in the nature of exact dimension.
No useful purpose is served, and much valuable time is wasted, in attempts to accomplish freehand, forms that may be perfectly achieved by proper implements. Familiarity with the use of these will be found of great assistance in all design in which geometric construction, apparent or not, plays so large a part.
Of this the average beginner has little conception, and though Geometry has been a subject of their early training, they seldom have any clear idea as to its employment in design. Except in few instances, they are unpractised in the use of geometrical instruments, and at times oblivious that these serve any practical purpose.
Mathematical Equipment
In design, where accuracy is of paramount importance, a reasonable equipment is imperative. Drawing boards vary in size, but for most ordinary work the antiquarian will suffice; the best type being that commonly used in engineering and architectural offices, with battens for adjustment and invariably a steel guide for the T square.
Large T squares are more reliable on account of the wider head, the better sort being in mahogany with bevelled ebony edge. When accuracy is essential, the T square should only be employed for horizontal lines, those in a vertical direction being attained by the use of the set square, when the right angle can be assured by contact of the base of the latter on the edge of the T square.
Set squares indispensable for ordinary work are those of the angles of 45 degrees and 60 degrees. They should be large, about twelve inch, and in celluloid, which, being translucent, tends to greater accuracy.
Bevelled set squares, usually in mahogany with ebony edge, are desirable when the ruling pen is used, and should be placed with the bevelled side to the surface of drawing as a precaution against blotting through the ink running off the edge from the pen. For the same reason the edge of the T square should be slightly tilted, so as not to be in contact with the drawing when ruling lines with the pen.