Lengths of wood usually run as listed, the Actual Length being the same as the Nominal Length. But you cannot always count on the mill's squaring up the ends, particularly in the lower-priced grades of wood, and you may have to square them up and cut them yourself, thus losing a half-inch or so. Therefore it is well to examine and measure your wood first, and then plan how best to utilize it, before rushing the project into production.

An exception to the rule regarding thicknesses of materials as cited above will be found in the "manufactured boards." In making plywood, hardboard, asbestos boards, Transite, insulating boards, and so on, the listed sizes become Actual Sizes. Thicknesses of 1/2 inch, 3/4 inch, 5/8 inch, or whatever they may be, will measure approximately that. The length and width of the piece will also be accurate-commonly these boards are 4'o"x8'o". In certain of the boards other sizes have been developed in modular dimensions which will tie in with the 4'X8' sheets, and these sizes, too, are Actual Size.

. . . plywood
One of the most versatile and useful of the modern developments in the woodworking field is plywood. Recent years have seen many innovations in this material so that now plywood can by purchased to do practically any job for which you may wish to use wood. Almost invariably when plywood is specified for projects in this book outdoor grades are required. Several manufacturers make the claim that their products are so waterproof that they may be boiled without the various layers of wood separating, so they are safe to use outdoors.

Plywood is available in many grades. The best grade should be good on both sides, with no knotholes or other mars in the surface, should be sanded smooth, and should have good, square, unmarred corners.