STANDARD SIZES OF LUMBER As there were no well-defined grades in the early lumber manufacturing operations, so also was there little uniformity in the sizes to which the various classes of lumber were cut. In the early days, boards and larger material were shipped in the rough to planing mills at points of consumption, where they were dressed and worked to the desired sizes. With the development of the lumber industry and the greatly increased variety and efficiency of machinery, the manufacturers gradually began to work their products into forms suitable for final use. This process has gone on until to-day nearly every large sawmill which supplies car trade has a fully equipped planing mill in which lumber is dressed and worked into flooring, ceiling, shiplap, siding, partition, molding, etc., so that a practically complete bill of materials for a house can be shipped from the mill.
This advance in the development of lumber manufacturing makes the question of standard sizes as important as that of standard grades. In fact, the two naturally go hand in hand; and specifications for widths and thicknesses of dressed lumber are commonly a part of the grading rules of the associations of manufacturers.
There is some variation, according to species, in the lengths and widths of rough lumber made in the sawmills. Since the softwoods are the more common structural material, and hence used in the entire piece, the dimensions vary somewhat from those of the hardwoods, of which the bulk are cut to new sizes in the process of re-manufacturing. The standard lengths of softwoods are commonly in multiples of 2 feet, beginning at 4 or 6 feet; and standard widths, in multiples of 2 inches, beginning at 4 inches. This is upon the theory that these dimensions are best adapted to the requirements of ordinary building operations for the placing of studding, joists, etc. In the hardwoods, standard lengths are usually in both odd and even feet, and standard widths in both odd and even inches. The
most notable exception to these rules is in the manufacture of hardwood flooring, in which dimensions as small as 1 inch in width, 7 inches in length, and % inch in thickness are produced.
each association of lumber manufacturers has standards for working lumber, which are recognized within its territory, these standards frequently do not coincide with the standards of other associations. There is a much greater diversity in this respect than is desirable from the standpoint of the consumer; and doubtless in time, a greater uniformity will be brought about in standard sizes for all the more common kinds of lumber. The present standards for flooring, ceiling, shiplap, partition, boards, etc., for the principal commercial woods, are given in Table 10, in which the nominal dimension is named, together with the actual size of the finished product. The nominal dimension is the size which is figured in calculating the quantity of lumber sold, and is based upon rough stock; while the actual dimension indicates the actual width and thickness of the final product. For example, a piece of 1x4 Norway pine flooring is 13/16 inch thick, with a face. That is, allowing for tongue and groove, each piece of flooring covers inches of floor space. Since it is important that the user of lumber should know the exact sizes specified for the principal woods, the table is made as complete as the information at hand permits. In several cases where standard sizes have not been officially incorporated in association rules, the sizes made by the leading manufacturers are given.
Table 10 Standard Sizes of Different Kinds of Lumber Flooring (INCH) F=Face. Width and thickness of tongue is I inch, and dimensions of groove 1/32 inch greater.
Woods Thickness and Width (Inches) White and Norway Pine (Nor. Pine Mfrs. Ass'n) ....1x4 is 13/16x31 F; 1x6 is 13/16 x5} F.
North Carolina Pine (North Car. Pine Ass'n) ....1x3 is 13/16x21 F; 1x4 is 13/16 x34 F; 1x6 is 13/16x5i F.