Evaluation of Some Tropical Woods Imported Into the United States from South America

The wood from six groups of tropical woods was examined to determine the species composition imported under the common names of andiroba, azafran, banak, hura, sajo, and virola. The andiroba group was identified as Carapa guianensis. Two species, Zanthoxylum sp. and Cordia sp. were included in the azafran shipment. The lumber designated as banak also included two species, Osteophloeum sp. and Virola sp. The hura group was identified as Hura sp. Sajo was identified as Campnosperma panamensis, and the lumber designated as virola included Dialyanthera sp. The six groups of tropical woods, together with yellow poplar (Liriodendron tulipifera) as a comparative control, were conditioned to a moisture content of 6 percent and subjected to a series of machining tests in general accordance with ASTM Standard D 1666-64. Planing tests were made by using the top head of a molder which was equipped with a 3-knife, T-slot cutterhead. Cutting angles used were 15, 20 and 30 degrees. Feed rate was adjusted to produce 20 knife marks per inch and depth of cut was 1/16 inch. Each specimen was examined for raised grain, torn grain, fuzzy grain and chip marks and assigned a grade of 1 to 5 with grade 1 representing a defect-free condition. In these tests the 15? cutting angle resulted in the highest percentage of defect-free pieces for all species. Other machining tests (boring, mortising, turning, shaping) were made and test specimens were graded on a basis of 1 to 5. Gluing tests were made using two adhesives: polyvinyl acetate and urea formaldehyde. Strength properties of the adhesive bonds were determined in accordance with ASTM D 905-49 and D 805-63 by shear in compression loading. Bond strengths tended to decrease with decreasing specific gravity and were somewhat similar for the two adhesives tested although wood failure was slightly higher for the polyvinyl adhesive. Static bending tests and toughness tests were conducted using the procedures of ASTM D 143-52 for small clear specimens. Andirob generally had the highest strength values.

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