Joists

These are the same as narrow planks, but of some fixed width, as 2 " by 3 ", which is the same as a 3 " strip sawed from the edge of a 2 " plank.

Fig. 32.

Fig. 33.

Most of the lumber you will require is sold by the square foot, at so much an M (1000 feet), or so much a foot. The square foot has an area of 144 square inches and is one inch thick, or contains 144 cubic inches, regardless of the shape or size of the piece. That is, Figs. 32, 33, and 34 each equal one square foot by board measure.

Thus a board 12' long, 12" wide, and 1" thick, contains 12 feet, board measure. A board 12' long, 6" wide, and 1" thick, contains 6 feet. A plank 12' long, 12' wide, and 2" thick, contains 24 feet. A plank 12' long, 6" wide, and 2" thick, contains 12 feet, or the same as the board first mentioned. You can bear in mind that in case of boards 12' long the contents in feet is indicated by the width in inches, as you will see from the examples just given. A board 12' long and 7" wide contains 7 square feet. So all you have to do to measure 12' stock is to find the width in inches. If the board tapers in width, measure at the middle. The same is true of planks, only the width in inches must be multiplied by the thickness of the plank. A plank 12'long, 7" wide, and 3' thick, contains 21 square feet. Of course this principle can be quickly applied to pieces whose length is any convenient multiple or fraction of twelve. Thus a board 18' long, 8' wide, and 1" thick, contains 1 1/2 times as many square feet as one 12' long, or 12 feet. A plank 9' long, 6" wide, and 2" thick, contains 3/4 as many square feet as if 12' long, or 9 square feet.

Fig. 34.

Boards less than one inch thick are usually sold by the square foot of surface, regardless of thickness - the price varying according to the thickness, except in cases where an inch board is planed down, when, of course, inch thickness is charged for. There is no distinction made in measuring between a rough board 1" thick and a planed board 7/8", as, of course, they represent the same amount of lumber. The cost by the foot of the planed board is greater because of the expense of planing. In cities, and sometimes in the larger towns, you can find thin boards (1/2", 3/8", 1/4", 3/16", 1/8" thick) already planed, and even scraped, for nice work.

Some of the rarer and less commonly used woods are often sold by the pound, as ebony, leopard wood, tulip wood, etc. Pieces turned out in quantities for special uses, as strips, mouldings, etc., are often sold by the "running foot," meaning simply the length, the price varying according to the amount of lumber and labour required. Certain regular sizes and shapes of lumber are sold by the hundred or by the piece. Shingles, clapboards, laths, and the like, are sold in bunches or bundles.

For other matters relating to wood, see Appendix.