Using The Scale. In using a scale, the workman must learn to think in feet and inches. It is a great temptation to the novice, because it seems the easiest way, to reduce the desired measurements of feet and inches to inches and fractions of an inch. For instance, if in working with a three quarter inch scale, or 3/4" = 1' 0", the desired dimension is 6' 8", the easiest way seems to be to reduce it to standard inches, and to say five inches. This is wrong; for, when working with an intricate fraction, or an unusual scale, say, 1" = 1' 0", it will be hard to measure or reduce it to a workable fraction if using an ordinary rule.

The 1" and the 1/2" scales are awkward, as the ordinary rule is divided into sixteenths of an inch, and therefore hard to adapt to measuring twelfths of a foot; thus the scales most generally used are those which are adaptable to a sixteenth of an inch, for instance, the 1/8", 1/4", 3/4", 1 1/2", and 3" scales.

In a 1/8" scale, 1/16"=6". This scale is adapted only to work upon large buildings, and is the smallest which the average woodworker is likely to use, though on large, general, or assembled drawings of a group of buildings, the 3/32" or 1/16" scales are sometimes preferred. The 3/16" scale is occasionally used, in which 1/16"=4". The 1/4" scale is the usual scale for small and medium-sized buildings in drawing the floor plans and elevations. In this scale, 1/16"=W\ The 3/4 " scale is frequently used in showing details and sections of construction. These are often placed upon the same sheet of drawings as the smaller drawing that they are to explain, references being made between them either by letters or figures. In this scale, 1/16"=l".

The l 1/2" scale is used for the same purpose as the 3/4" scale, and this, or any large scale, may be used for making drawings of furniture and other fittings. In this scale, 1/8" - 1". The 3" scale is used for the same purpose as is the 3/4" and the l1/2"; but, being larger, it allows more accurate drawing and scaling. In this scale, 1/4" = 1". Full-sized drawings are usually made of important details. Figure 83, A, shows a part of a 1/4" scale, and B, a part of a 3/4" scale. The distance indicated at A is 4' 5" ; and at B, it is 2' 9". In using a scale to measure an unknown distance from a drawing, - for instance, either of the above spaces, - place the graduation 0 on the line at one side of the space, as at c; then move the scale to the nearest smaller graduation of feet at the other extreme of the distance to be measured, as at d. In measuring the distance at A, move the scale to the right, and at B, to the left, a distance equal to that between d and the smaller graduation of feet; then read the feet and inches as shown upon the scale.

In using an ordinary rule as a scale, the workman will find it more convenient to use the edge which is divided into sixteenths, as indicated in Fig. 84. In using the rule for this purpose, it is tipped upon its edge to bring the graduations nearer the work, and the end of the rule is placed upon the line at one end of the space being measured. The number of feet and inches are then computed, we will say to a 1/4" scale, the distance 2 3/16" being reduced to feet and inches by the following mental process: 1/4" = 1': 8x1/4 = 8'; 3/16" = | of V = 9" ; thus we obtain 8' 9". In working with a 3/4" scale, by applying the same mental process, we obtain 2' 11". If a 1 1/2" scale is being used, it will read 1' 5 1/2". The rule commonly used by most woodworkers is adaptable for scaling by the above method, but a brass-bound rule, which is generally scaled, or some other form of a scaled rule, is preferred by many.

Fig. 83. - Use of Scales.

Fig. 84. - Use of the Rule in Scaling.