Architect’s Scale ARCHITECT’S SCALES are usually triangular in
shape and are used wherever dimensions
are measured in feet and inches. Major
divisions on the scale represent feet which, in
turn, are subdivided into 12ths or 16ths, depending
on the individual scale.
Figure 224.Architect’s scale.
Figure 224 shows the triangular architect’s scale.
Also shown are segments of each of the eleven
scales found on this particular type of scale. Notice
that all scales except the 16th scale are actually
two scales that read from either left to right
or right to left. When reading a scale numbered
from left to right, notice that the numerals
are located closer to the outside edge. On
scales that are numbered from right to left, notice
that the numerals are located closer to the inside
edge.
Architect’s scales are "open" divided (only the main
divisions are marked throughout the length) with
the only subdivided interval being an extra interval
below the 0ft mark. These extra intervals
are divided into 12ths. To make a scale measurement
in feet and inches, lay off the number
of feet on the main scale and add the inches
on the subdivided extra interval. However, notice
that the 16th scale is fully divided with its divisions
being divided into 16ths.
Now let’s measure off a distance of 1 ft 3 in. to
see how each scale is read and how the scales compare
to one another. (Refer to fig. 224.) Since the
graduations on the 16th scale are subdivided into
16ths, we will have to figure out that 3 in. actually
is 3/12 or 1/4 of a foot. Changing this to
16ths, we now see we must measure off 4/16ths to
equal the 3in. measurement. Note carefully the value
of the graduations on the extra interval, which
varies with different scales. On the 3
in. = 1 ft scale, for example, the space between adjacent
graduations represents oneeighth in. On the
3/32 in. = 1 ft scale, however, each space between
adjacent graduations represents 2 in. The
scale 3/32 in. = 1 ft, expressed fractionally, comes
to 3/32 = 12, or 1/128. This is the smallest
scale provided on an architect’s scale. The scales
on the architect’s scale, with their fractional equivalents,
are as follows:

