ABC of the Steel Square and Its Uses

by Fred. T. Hodgson

On the sixth line under 8 are the figures 9 and 10. By placing square on stock to be cut at these figures, 9 on body and 10 on tongue, and marking on the 10 side, this gives side cut of hip or valley rafter against ridge board or deck.

On the seventh line under 8 are figures 12 and 10. By placing square on stock to be cut at these figures 12 on body, 10 on tongue, and marking on the 10 side this gives the cut of sheathing and shingles in valley or hip.

Remarks.—To obtain the lengths and cuts be careful to use the figures under whatever figure your roof raises to the foot. If your roof raises 12 inches to the foot, or half pitch, look under 12, and so on in all cases. In cutting jack rafters allow for half the thickness of hip or valley rafters as lengths given on square are to center lines.

Note.—The figures on the square, giving side cuts of jacks, will also give the correct miter cuts for moulding in the valley at the junction of two gables, also miter cuts for gable mouldings where it intersects with level mouldings at the end of building.

The figures giving cuts of sheathing in valley or hip also give cuts for mitering level planceer with gable planceer, also the miter cuts where two gable planceers intersect, also the cut for planceer on gable end.

To obtain the bottom and top cuts of hip or valley rafter use the figure 17 on body, and whatever figure your roof raises to the foot on tongue. This will give you the correct cuts in all cases.

To obtain the bottom and top cuts of common rafters and jack rafters use the figure 12 on body, and whatever figure your roof raises to the foot on tongue. This gives correct cuts in all cases. Always remember that the cut comes on the tongue, or last named figure. It is so arranged in all cases.

Octagon, “Eight-square” Scale.—This scale is along the middle of the face of the tongue, and is used for laying off lines to cut an “eight square” or octagon stick of timber from a square.

Suppose the figures A, B, C, D, [Fig. 2], is the butt of a square stick of timber 6×6 inches. Through the center draw the lines AB and CD parallel with the sides and at right angles to each other.

With the dividers take us many spaces (6) from the scale as there are inches in the width of the stick, and lay off this space on either side of the point A as Aa and Ab; lay off in the same way the space from the point B as Bd and Be; also Cf and Cg and Db and De. Then draw the lines ab, cd, cf and gh. Cut off the solid angle E, also F, G and H; there is left an octagon, or “eight square” stick. This is nearly exact.