Structural Flakeboards and Composites 3007 



published, but the following references provide background information on 

 particleboards of other species: 



Reference Subject 



National Particleboard Association 



(1968) Screw holding of particleboard. 



Whittington and Walters (1969) Withdrawal loads of screws in soft maple and 



particleboard. 



Carroll (1970, 1972) Overdriving of screws in particleboard, and mea- 

 suring screw withdrawal resistance with a 

 torque wrench. 



Didriksson et al. (1974) Splitting of wood-base building boards caused by 



insertion of screws in panel edges. 



Eckelman (1973, 1974, 1975) Holding strength of screws in hardwoods, parti- 

 cleboards, and other wood-based materials. 



Superfesky (1974) Withdrawal resistance of sheet-metal screws from 



particleboard and medium-density hardboard. 



Barnes and Lyon (1978a) Withdrawal loads in weathered and unweathered 



particleboard decking. 



24-13 FRICTION COEFFICIENT 



Friction coefficients of steel on solid wood are given in section 9-4. The 

 friction coefficient of interest during application of roof sheathing is not that of 

 wood-to- steel, however, but rather that of sheathing-to-shoe sole. Since carpen- 

 ters' shoes may be soled with leather, neoprene, or crepe rubber composition, all 

 three are of interest. 



These three shoe sole materials (all smooth, i.e. , not textured) were evaluated 

 (table 24-24) on four wet and dry sheathing materials: unsanded CDX southern 

 pine sheathing plywood (across the face grain), and flakeboard of mixed south- 

 em hardwoods having randomly oriented 0.015-inch-thick face flakes and 

 smooth surfaces (fig. 24-45 left), fine-screen textured surfaces, and coarse- 

 screen textured surfaces (fig. 24-45 right). 



For dry sheathing the highest average static coefficient of friction was 

 obtained on coarse-screen flakeboard (.876). For wet sheathing, best average 

 results were on plywood (.820). The best combination on dry sheathing was 

 crepe soles on coarse-screen flakeboard (1.218). Crepe soles on wet coarse- 

 screen flakeboard also did very well (0.938). 



Szabo and Nanassy (1979) found from a study of aspen flakeboard and 

 western softwood plywood that plywood and screen-back waferboard had simi- 

 lar coefficients of kinetic friction with common shoe sole materials when tested 

 dry. They also found that neoprane and rubber are the safest sole materials for 

 footwear of men working on wooden roof decks; piles of plywood or screen- 

 back aspen waferboard can slip at slopes greater than about 20 degrees. 



