JOINTS IN WOODWORK 



75 



As all timber shrinks, the bolts should be examined at intervals, 

 and tightened up if necessary. 



Halving. — Halving has already been referred to in connection with 

 the lengthening of timbers. The method may also be employed for 

 the purpose of uniting two scantlings 

 at right angles. This is shown in 

 Figs. 77, 77a, 78, and 78a. 



In Fig. 78 the surfaces are bevelled, 

 giving a sort of dovetail halving, which 

 is often used for connecting wall- 

 plates at the corners of buildings. 



Fig. 77a. 



m 



3-"-, 



Fig. 78. 





btM 



W/tLL PlHTES, 



,OOv£Tfl/LED JOINT. 

 Fig. 78a. 



Mortise and Tenon Joints. — Tenon joints are used extensively 

 in framing. A tenon is formed by cutting away equal rectangular 

 pieces from each side of the end of a scantling. The middle portion, 

 or tenon, so left is usually given a thickness equal to one third that 

 of the scantling on which it is formed. The rectangular hole, or recess, 

 cut in the other scantling in order to receive the tenon, is called a 

 mortise. 



Figs. 79 and 80 show two forms of mortise and tenon joints. 



Haunched Tenon Joints are illustrated by Figs. 96 and 97. The 

 haunch increases the strength of the joint considerably. 



Tenon joints, besides being glued, may be pinned (Fig. 79) or 

 wedged (Fig. 96) with |-inch wooden pins or wedges. If wedges are 

 used the mortise is made a little wider at its outer end, to receive them. 

 The wedges or pins are dipped in glue before being driven into place. 

 In outside work, however, white lead is preferable to glue. 



