SOME EXAMPLES OF TIMBER TESTS 



THE cuts on the five succeeding pages illustrate very clearly the 

 nature and the methods of some of the work done in one depart- 

 ment of the forest products laboratory that of timber tests. 

 Machines of great simplicity, but efficiency, have been devised for deter- 

 mining the strength of wood under different kinds of strain. 



Figure i shows a bridge tie of western yellow pine which was 

 broken by the blow of a 51 5-pound hammer falling twenty inches. 



Figure 2 shows a similar piece of timber which sustained under 

 gradual loading a maximum load of 2,380 pounds, concentrated at two 

 points equally distant from the center and one-third of the space apart. 



Figure 3 shows a white pine packing box which sustaind a maxi- 

 mum load of 1,3/0 pounds, applied at diagonally opposite corners. This 

 box was eighteen by twenty by thirty inches in size. 



Figure 4 shows the manner of testing hickory buggy spokes. 



Figure 5 shows the results of tortion or twisting tests upon sticks 

 of red gum and four commercial grades of hickory. 



These tests were made some years ago, but they are typical of the 

 work done in the section of timber tests. With the new equipment, the 



section will be able to do a much more comprehensive work in the future. 



409 



