2636 Chapter 22 



DECKBOARD AND STRINGER MANUFACTURE 



Mount (1971) found that about 55 percent of the pallet manufacturers in West 

 Virginia, Pennsylvania, and Maryland purchased random-length long lumber, 

 about 35 percent random-length cants, and about 10 percent cut-to-size pallet 

 shook. Since that time cutting of pallet shook from random-length cants has 

 increased. Also since 1970, equipment has become available to economically 

 cut lumber from short, low-grade hardwood logs (6 to 12 feet in length). Most 

 recently, mills have been designed to rapidly make pallet shook from bolts cut to 

 deckboard or stringer length (36 to 50 inches). Brief descriptions of these 

 options follow. 



From random-length long logs. — Sawmills appropriate for long hardwood 

 logs are described in section 18-10, and chipping headrigs suited to hardwoods 

 are discussed in section 18-9. Usually upper grades of lumber from such logs are 

 sold to the furniture trade, and the lower grades are utilized for pallets, contain- 

 ers, flooring, and crossties. Lumber grade yields are tabulated in chapter 12. 

 Readers interested in an economic feasibility study, with flow plan and illustra- 

 tions of machines, will find Koch's (1957) analysis useful; although some of the 

 machine designs have been improved during the years since this study was 

 made, the flow diagrams are still appropriate for random-length hardwood logs 

 of low grade. 



From short logs. — Lumber manufacture from short logs is illustrated in 

 figures 18-104ABCD, 18-105, 18-106, 18-109, and 18-113 through 18-123. 

 Economic feasibility studies of the short log system in pallet manufacture are 

 summarized in sections 28-3, 28-11, and 28-17. 



From random-length cants. — Development of reliable, thin-kerf, circular 

 gangsaws for hardwood cants (see figs. 18-76 and 18-77 and related discussion) 

 greatly simplified pallet shook manufacture. By combining a cant infeed deck 

 with a cut-off saw, a gang ripsaw, and a stacker, a two-man crew can saw and 

 stack up to 4,000 board feet of pallet shook per hour. Numerous designs of these 

 simple production lines are available; that illustrated in figure 22-37 is typical. 



From deckboard- and stringer-length bolts. — Application of the shaping- 

 lathe headrig should facilitate highly efficient use of low-grade small hard- 

 woods. Crook and major defects are eliminated from stems by cross-cutting 

 them to deckboard or stringer length (36 to 52 inches) before conversion. 

 Operating principles of shaping lathe headrigs are illustrated in figure 18- 

 104ABCD; economic feasibility studies of pallet manufacturing operations built 

 around them are summarized in sections 28-17, 28-26, and 28-32. In one 

 configuration, presorting of bolts for length and diameter ahead of the headrig is 

 not necessary. The scanner and automatic setworks incorporated in the 54-inch 

 machine permit it to process bolts of random diameters from 5 to 26 inches and 

 lengths from 36 to 52 inches while automatically converting them to square, 

 rectangular, octagonal, or cylindrical patterns to optimize yield at ripsaw or 

 veneer lathe (fig. 18-104D top). Production rate is six or seven bolts per minute. 

 Residue can be in the form of flakes (fig. 28-19) or pulp chips (fig. 28-20 

 bottom). 



