To enlarge a design, place tracing point at b, and fasten original design under it to drawing board with thumb tacks.
Under c fasten a sheet of drawing paper. With the right hand at b, trace the design by carefully sliding tracing point along the lines. At the same time, with the left hand keep pencil point at c sufficiently in contact with the paper to make a clear line.
To reduce a drawing, reverse b and c, bringing pencil point and paper to b, and original to c. Pass tracer over design at c, and the reduced design will be traced at b. Different proportions between original and reproduction may be obtained by shifting the position of pivots e and f.
[Fig. 208] shows pivot e shifted to position h. As distance c e should always equal distance d f, it now becomes necessary to move pivot f to point g. By remembering this rule, and placing pivots in various positions, a wide range of proportions is possible.
THE DRAWING TABLE
A table to hold the drawing board should be not less than 3 feet 2 inches high, as much of the work is performed standing up. A stool with revolving seat should be provided for the draughtsman to sit on occasionally.
The table top may be made slanting, but it is better practice to have a heavy flat top of pine, which may be used as a large drawing board itself, and to provide for the slant by using a triangular block under the farther end of drawing board. Two or three blocks may be made, about two feet long and of different sizes, to give different degrees of slant.
Tables for this purpose are often made with tops, which may be adjusted at different angles, and the young designer may try his inventive talent in this large field, but any arrangement which will bring an element of instability is to be studiously avoided. The drawing table should be as solid and rigid as possible.
The design in [Fig. 209] was made by our boys, and has proved very satisfactory. It has much of the mission style about it, with its square legs and mortised joints.