Measures and yields of products and residues 3295 



The volume, in board feet, of clear-one-face and better furniture cuttings 

 produced from three grades of white oak bolts is given in table 12-33. In terms of 

 percent of total bolt volume, maximum yield was 76 percent obtained with 12- 

 and 13-inch bolts 4 feet long. 



In addition, nomographs have been developed to predict cutting yields from 

 2- to 7-foot-long bolts of yellow-poplar and red maple (based on first ripping, 

 then crosscutting, then re-ripping if required) as follows: 



Yellow-poplar 



clear-two-face fig. 18-126 



clear-one-face fig. 18-127 



sound character marked fig. 18-128 



Red maple 



clear-two-face fig. 18-129 



See page 1982 for directions on how to use the nomographs. 



Yield of clear-two-face cuttings from standard grades of long lumber. — 



Hallock (1980) developed nomograms (figs. 27-14A through 27-1 8B) to deter- 

 mine furniture cutting yields from hardwood lumber of various grades when that 

 lumber is initially processed by gang ripping rather than by the more convention- 

 al crosscutting. The first one of the nomogram pair for each lumber grade shows 

 in percent of total lumber surface area the yield of specified length, clear, two- 

 face cuttings when the lumber is gang ripped into 1-inch widths. The second 

 nomogram of each pair shows how to adjust yield values for gang rip widths 

 other than 1 inch. A rip width table (table 27-120) shows the gang rip width that 

 promises the highest yield for each cutting length. 



The following example illustrates how to use the nomograms."^ 



Assume a relatively simple cutting bill is to be cut from No. IC lumber. The 

 cutting sizes and required numbers arranged in descending order of length are: 



Length Width Number 



Inches 



60 X 3.5 100 



48 X 4.0 600 



26 X 2.0 300 



12 X 6.0 100 



The longest cutting (60 inches) is known as the "primary" cutting and the 

 other cuttings (48, 26, and 12 inches) as "subsequent" cuttings. 



It is first necessary to refer to table 27-120 for the gang rip width which 

 promises the highest yield for the primary (60-inch) cutting length from No. IC 

 lumber. Table 27-120 shows the 1 .5-inch width to be best for all cutting lengths 

 from 68 to 28 inches. 



Use of a standardized data form similar to table 27- 1 2 1 for recording observed 

 and calculated values will greatly simplify the prediction computations. Consid- 

 er first only that part of table 27-121 above the head "second calculation." 

 Cutting sizes are entered sequentially with the longest first and the shortest last. 

 The number of cuttings of each size is entered in the second column and total 



'^he example is reproduced from Hallock (1980). 



