ABC of the Steel Square and Its Uses

by Fred. T. Hodgson

The following table, which was prepared especially for this square, shows the manner of working the square:

Fig. 10.

RAFTER TABLE DIRECTIONS.

The rafter table and the outside edge of the back of the square, both on body and tongue, are in twelfths. The inch marks may represent inches or feet, and the twelfth marks may represent twelfths of an inch or twelfths of a foot (that is, inches) as a scale. The rafter table is used in connection with the marks and figures on the outside edge of the square.

At the left end of the table are figures representing the run, the rise and the pitch.

In the first column the figures are all 12, which may be used as 12 inches or 12 feet, and they represent a run of 12.

The second column of figures is to represent various rises.

The third column of figures in fractions represents the various pitches.

These three columns of figures show that a rafter with a run of 12 and a rise of 4 has 1-6 pitch, with a run of 12 and a rise of 6 has 1-4 pitch, with a run of 12 and a rise of 8 has 1-3 pitch,