No. 18. A dovetail halving or lap-dovetail is a middle-lap joint with the pin made dovetail in shape, and is thus better able to resist tension. It is used for strong tee joints.
Fig. 265-18 Dovetail halving
No. 19. A beveled halving is made like a middle-lap joint except that the inner end of the upper member is thinner so that the adjoining cheeks are beveled. It is very strong when loaded above. It was formerly used in house framing.
Fig. 265-19 Beveled halving