## Architects Scale

Architectural scales are normally flat or triangular in shape and come in different lengths, the 12-inch (30-cm) triangular shape being the most popular. All three sides of the triangle scale (except those with a 12-inch scale) contain two scales on each usable surface. Each of these scales uses the full Figure 4.2B A drawing showing dimension lines terminating at the extension lines with arrows at the endpoints. Figure 4.1 shows slashes at the endpoints, and Figure 3.8C shows dots at its end points. DIAMETRAL DIMENSION Figure 4.3 A drawing with examples of diametral and radial dimensions.

length of the instrument: one is read from left to right and the other from right to left. Likewise, a scale is usually either half or double that of the scale it is paired with. For example, if one end is a 1/8-inch scale, the opposite end is a 1/4-inch scale; the opposite end of a 1 1/2-inch scale would be a 3-inch scale.

The scales are designed to measure feet, inches, and fractions of an inch. Below are the most common scales found on the triangular architect's scale with their approximate metric equivalent in parentheses:

• 1/32 inch = 1 foot (1/400 metric equivalent—often used for site plans—actual 1/384)

• 1/16 inch = 1 foot (1/200 metric equivalent—often used for large projects and small site plans— actual 1/192)

• 1/8 inch = 1 foot (1/100 metric equivalent—actual 1/96)

• 1/4 inch = 1 foot (1/50 metric equivalent—actual 1/48) Figure 4.4A An Illustration showing different triangular scales. Figure 4.4B An Illustration of 6-inch scales

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Figure 4.4B An Illustration of 6-inch scales Figure 4.4C A typical architect's scale showing end view.

• 3/8 inch = 1 foot (no precise metric equivalent—actual 1/32)

• 1/2 inch = 1 foot (1/20 or 1/25 metric equivalent—actual 1/24)

• 3/4 inch = 1 foot (no precise equivalent—actual 1/16)

• 1 inch = 1 foot (one-twelfth full size—approximate equivalent 1/10)

As an example, when used on a typical floor plan that is 1/8-inch scale, each 1/8 inch on the drawing represents 1 foot of actual size. The same applies for a 1/4-inch scale in that each 1/4-inch segment on the drawing represents 1 foot of actual size. The same approach applies to other scales.

There is no strict convention for which scale is used on which drawings, although certain parts of a set of drawings are traditionally drawn to certain scales. For example, most floor plans and elevations are in 1/8- or 1/4-inch scale, depending on the size of the building and sheet. For residential structures, the 1/4-inch scale is usually used, roughly equivalent to 1:50 in metric scale (Figure 4.5). For large commercial buildings, smaller scales may be used. Exterior elevations are often drawn to 1/4-inch scale. Sections and cross-sections may be drawn to 1/4-, 1/2-, or 3/4-inch scale if the section is complex. Depending on the amount of information presented, construction details can vary from 1/2- to 3-inch scale and even full-size scale for certain millwork details (Figure 4.6). 