mitted is increased and the proportion of clear wood required is decreased. In the lowest grade the quality of the cutting is reduced from clear face lumber to sound lumber; all grades above the lowest 18 are based on clear face cuttings. By far the largest proportion of the hardwood is purchased in industrial or shop grades; therefore, an outline of the basic principles of the system may be of interest to the more than casual reader, and it is very briefly summarized at the conclusion of this chapter. A major purpose in including a somewhat technical description of the industrial grades is to correct a false impression that many persons have regarding the relation of rough lumber grades to a finished hardwood product. It is not unusual in specifications for hardwood products, such as doors, sash, interior trim, or even such highly fabricated articles as desks, to require that a certain grade of hardwood be used in construction. To insist upon such requirements is usually unnecessary and a burden on the manufacturer. Since the lumber which actually gets into fabricated articles is most frequently clear (without apparent defects), such as in furniture, it is of no interest to the consumer whether the grade used is the highest or lowest, so long as the cuttings used are clear. OUTLINE OF STANDARD HARDWOOD GRADES In setting up grades for a product with so many variations as are found in hardwoods, it was found necessary to establish a few basic grades which could be used as models for the large number of species. These models are called "standard grades," of which there are eight. All variations from the "standards" are designated as "exceptions." In the book of rules each important species is taken up in detail, and all "exceptions" to the "standard rule" are specified.19 The eight standard grades are as follows: (a) Firsts In practice these two standards are usually combined and (b) Seconds sold as one grade, called "firsts and seconds.' (c) Selects (d) No. 1 common These two standards may be sold as separate grades or combined as one grade, called “No. 1 common and selects." (e) No. 2, common. Firsts and Seconds is a combined grade and, as the name suggests, is the best of the standard grades. It contains a large amount of clear lumber; the smaller pieces allowed in the grade must contain as much as 91% percent "clear face cuttings." The minimum for even the larger pieces is 8313 percent clear face cuttings.20 The grade is also characterized by a high average length and width. Selects is a very high grade, being composed of pieces that grade Seconds or better on the best face," with the reverse face sound or not 18 The only exception is in the grade of "Sound wormy." "Cuttings" for this grade are clear except for small holes. (See description of "Sound wormy" on p. 65.) 19 Example: All grades of plain white oak are "standard" with no exceptions listed. But under maple, two of the eight "standard" grades are qualified by "exceptions." 20 The size of the "cuttings" and the number of "cuttings" permitted in each board depends upon the surface area of one face. Large boards may contain smaller and more numerous cuttings than small boards, 21 Inspection of all grades must be made from the poor side of the piece, except when otherwise specified. Certain large boards in the "select" grade are excepted from this rule. below No. 1 Common. It has a somewhat lesser average length and width than Firsts and Seconds. No. 1 Common: Some of the smaller pieces are required to have not less than 75 percent "clear face cutting," and the larger pieces not less than 662% percent. It has a somewhat lesser average length and width than Selects. No. 2 Common: Some of the smaller pieces are required to have 66% percent "clear face cutting," and the larger pieces not less than 50 percent. Sound Wormy is a specialized grade in which worm holes and other small defects are permitted in the cuttings. With the exception of these defects, no piece shall be below the grade of No. 1 Common. The grade Sound Wormy is well adapted to certain products that have unexposed parts, such as vehicle frames, cloth-covered caskets, etc. No. 3A Common will admit pieces in which the "clear face cutting" is not less than 333 percent of their surface area. It will also admit pieces which will grade No. 2 Common on the best face, but the reverse face of the cuttings must be sound. No. 3B Common will admit pieces that cut not less than 25 percent in "sound cuttings." The widths and lengths may have a relatively short average, but are the same in this respect as No. 3A Common. PRINCIPAL USES OF HARDWOODS In the chapter on "Selection of hardwoods for specific purposes" (p. 46), it is pointed out that, with few exceptions, there are several hardwoods suitable for any given purpose and that a choice of a single wood depends largely upon particular factors subject to decision by the engineer or architect. The scope of this publication does not allow space to list in detail each and every wood suitable for each and every purpose. Specific information and data of this type may be obtained upon application to the Forest Products Laboratory, Madison, Wis. The following list of hardwood uses simply illustrates the large number of products commonly made from our native hardwoods; it should not be construed as being complete and all-inclusive: In table 3-appearing on succeeding pages-will be found figures showing the amounts of all the major American hardwoods used by our principal domestic industries during the calendar years 1928 and 1933: Table 3.-American Hardwoods Used by Domestic Industries in 1928 and 1933 1 1 From Lumber Used in Manufacture, report made by U. S. Forest Service for 1928 and 1933 only. The 1933 report did not include "planing-mill products," which fact partly accounts for the smaller total consumption as compared with 1928, although the stagnation of industrial activity in 1933 is responsible for the general decline in consumption. * 1933 includes lumber used for boxes and crates and for patterns and flasks by plants not classified as "wood-using industries." They were not included in 1928. 31928 figures included in "planing-mill products.” 4 Kitchen cabinets and refrigerators shown separately for 1933, but combined under "refrigerators and kitchen cabinets" for 1928. |