In all the above (except the dowelled and butt joints) it will be seen that any opening caused by shrinkage of the boards will be covered by the tongue, feather, or fillet, or (in the case of the rebated, and of the fillistered joint) by the projection below of the adjacent board.
In each of the joints illustrated in Figs. 293, 294, 297, part of the width of the board itself is taken up in forming the joint, so that a greater quantity of boarding is required to cover a given surface than if joints with detached tongues, fillets, or dowels are used, as in Figs. 295, 296, 298.
There are several elaborate forms of joint, consisting of double grooves and tongues of different lengths, combinations of the above, but they are too complicated for use in practice.