Measures and yields of products and residues 



3307 



At this point all cutting requirements have been met. It is entirely possible 

 with a longer and more complex cutting bill that more than the two calculation 

 charts used in this example would be needed to fill all requirements. It is 

 important to remember that, for each calculation chart, the longest remaining 

 cutting becomes the primary cutting and that a best rip width for its length should 

 be selected from table 27-120. 



In this example a total of 2, 173 feet (405 + 1 ,768) surface measure of No. 1 

 Common lumber would be required. However, 396.4 feet surface measure of 

 cuttings (column 11, second calculation table 27- 12 1,27 1.4 + 125.0 = 396.4) 

 would be either unused or used to develop short cuttings for another cutting bill. 



Yield of dimension stock from flitches. — Flitches cut l-Vi or 2 inches thick 

 from hardwood bolts are sometimes purchased by manufacturers of clear furni- 

 ture squares and random- width stock. Yields of cuttings from such flitches can 

 be predicted with the technique developed by Rast and Chebetar (1980). Basi- 

 cally, their procedure involves reducing the total possible yield (100 percent) by 

 the percentage of defect, which is determined as follows: 



1 . Visualize a grid divided in thirds or in quarters superimposed over the 

 flitch (fig. 27-19). 



2. Select the grid in which the fewest compartments contain defects. 



3. Deduct a percentage from total yield (100 percent) for the amount of 

 defect (fig. 27-19). The minimum deduction for flitches divided into 

 thirds is 15 percent; the minimum deduction for flitches divided into 

 quarters is 10 percent. 



4. If the defect deduction is 15 percent or less, deduct an additional 5 

 percent for cuttings and kerf. If the defect deduction is 20 percent or 

 more, no additional deduction is needed. 



I 





DEDUCT 

 15% 



DEDUCT 

 25% 



DEDUCT 

 25% 



DEDUCT 

 30% 



DEDUCT 

 35% 



i 



i 



DEDUCT 

 35% 



DEDUCT 

 40% 



DEDUCT 

 45% 



DEDUCT 

 50% 



DEDUCT 

 70% 



1 1 1 



IIlI 



DEDUCT 

 10% 



DEDUCT 

 15% 



DEDUCT 

 20% 



DEDUCT 

 25% 



DEDUCT 

 25% 



» I 



i 



DEDUCT 

 25% 



DEDUCT 

 30% 



DEDUCT 

 35% 



DEDUCT 

 40% 



DEDUCT 

 50% 



Figure 27-19. — Compartmentalization of defects in flitches by thirds (1/9 of area) or by 

 quarters (1/16 of area), and percentage to deduct from total yield for various sized 

 defects in flitches after compartmentalization by thirds (A) or by quarters (B). (Draw- 

 ing after Rast and Chebator 1980.) 



