74 



FARM BUILDINGS IN SOUTH AFBICA 



The joint illustrated by Fig. 76 is an oblique scarfed joint with 

 splayed ends, which is largely used, especially for lengthening posts 

 or uprights. Besides being suitable for compression it can also, 



Fig. 75. 



ZZ1 



Fig. 76. 



independently of the bolts, resist a certain amount of cross or bending 

 stress in one direction. 



Another type of scarfed joint, which is sometimes called a splayed 

 scarf with keys, is shown in Fig. 77. The joint is tightened by tapered 

 keys driven from opposite sides. It is well suited to resist all four 

 kinds of stress, viz. Compression, tension, cross-stress, and bending. 



Wall Plates, 

 halved jo/nt. 



Fig. 77. 



Size of Bolts for the above Joints. — As already pointed out the holes 

 for the bolts weaken the scantlings through which they pass. The 

 bolts therefore should not be larger than necessary ; the following sizes 

 are recommended : — 



For 41 ! 



by 3" or smaller scantlings use f -inch bolts. 



For timbers from 4J" by 3" up to 6" by 6" use J-inch bolts. 



For scantlings larger than 6" by 6" use f-inch bolts. 



Large washers should be placed under both bolt heads and nuts. 



