64 • Slightly cupped pieces 12" and wider which may be ripped so as to produce two pieces each of which would grade Bending Oak and each be sufficiently flat to dress uniformly to standard thickness for surfaced lumber, shall be admitted in this grade. This rule does not apply to specified widths.
HARDWOODS FOR CONSTRUCTION Note: The American Lumber Standards Committee has developed voluntary product standards for softwood lumber used primarily for construction, under procedures established by the U.S. Department of Commerce. The latest such standard, PS 20-70, serves as the basis for grade rules published by various regional associations covering species in different regions, ex. southern yellow pine, western softwoods, eastern white pine and spruce, etc. One such association, (Northeastern Lumber Manufacturers Association, P. O. Box 87A, Cumberland Center, ME 04021; Tel: 207-829-6901) has qualified some hardwood species to be graded under the National Grading Rule, PS 20-70. The following rules have been included for the convenience of users of the specifications that preceded the National Grading Rule, PS 2070, first published in 1970. These rules for hardwoods for construction may be used by mutual agreement between Buyer and Seller. The National Hardwood Lumber Association makes no warranty of representation that lumber graded under any of these specifications has any particular strength values or is suitable for a particular purpose.
Specifying Species White Oak comprises the species of the trees in the white oak group, commercially known as bur oak, chestnut oak, chinquapin oak, cow oak, live oak, overcup oak, post oak, rock oak, swamp white oak, and white oak, and includes also the other species of oak whose leaves have rounded lobes. Red Oak comprises species of trees in the red oak group commercially known as black oak, pin oak, red oak, scarlet oak, spanish oak, turkey oak, water oak, willow oak, and yellow oak, and includes other species of oak whose leaves have bristle-tipped lobes. Mixed Oak comprises the species of the trees in the red oak and white oak groups, regardless of the proportion of either group or any species. Mixed Hardwoods comprise the species of the oaks and the other broadleaved trees.