Sample ComDutatlon: 



To obtain the tensile strength of 3 ply wood consifting of 2-l/20-inch 

 birch faces and a l/l5-inch basswood cor^. 



Parallel to face grain = 2 x 1/2O x 19820 = 1182 riounds per inch 

 of width. 



Perpendicular to face grain = 1 x 1/I6 xl0,320 » 645 pounds per inch 

 of width. 



This computation neglects the tensile strength of the oly or plies 

 perpendicular to the grain, which is conparatively small, the 

 results are therefore slightly in error. 



*STiecific Gravity based on oven dry weight and volume tt tei;t. 

 **Ba8ed on total cross sectional area. 

 ***Baeed on essnnntion that center ply carries no load. 



Data baeed o^, teste of three ply panels v.ith all plies in any one 

 panel sane thickness and species. 



(1) Probably Plack Cherry 

 (£l " (ivergreen) Magnolia 

 *(3) " Khaya Sp. 

 (4) " Tanguile 

 ^5) " Silver Maple. 



70gorA 



£S. 



FOREST PRODUCTS LABORATORY 

 FOREST SERVICE- 

 U. S. DEPARTMENT OF AGRICULTURE 

 JANU.iRY 13, 1919. 



