SAW PERFORMANCE AND LUMBER CHARACTERISTICS WHEN PRODUCING PULPABLE SOUTHERN PINE SAWDUST
FOREST PRODUCTS LAB MADISON WIS
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Exploratory saw performance tests were made with 12-, 18-, and 36-tooth, 48-in.-diam circular saws to observe the effect of tooth form, tooth width, saw speeds, and feed rates on the roughness and dimensional variations of the lumber and the character of the sawdust particles produced. The operating conditions shown to be most practical were used to compare the performance of the 12- and 36-tooth saws in relation to width of sawing face, sawing accuracy, acceptability of the sawdust for pulping, and planing allowance necessary to remove board surface roughness. The economics of salvaging sawdust for pulp use was compared with gains from improved sawmilling practices. There was no appreciable difference in performance between the 12- and 36-tooth saws when operated below 600 rpm and taking the same bite. Thickness variation was greater than acceptable at bites greater than 14 in. and depths of cut of 7 in. or more. At the 14-in. bite required to produce 14-in. chips for the pulp and paper industry, from 532 to 832 in. of added thickness was required for surfacing as compared with 432 in. normal in the industry. The surface degradation more than offset the kerf chip value when using the sparse-toothed saw.