Pieces Laid And Joined Parallel To One Another.
As the width of a "board" is limited from 7 to 9 inches ("planks" are timbers, the thickness of which does not exceed four inches, and the width above nine inches; a "balk" is the large square timber in the form in which it is imported into this country), it is necessary in forming comparatively large and wide surfaces - such as a door - to join the boards together in the direction of their length. This is done in a variety of ways, the most commonly adopted of which are illustrated in figs. 370, 371, and 372. In fig. 370, at a a, the boards are simply planed square on their edges and secured together by nails; boards so prepared are said to be " shot," b b shows elevation. In same figure, c c section, d d elevation, illustrates the method of joining boards by "rebated" edges, and e e f g by "tonguing and grooving." Boards are also joined, as g, by inserting a feather or slip h in a groove made by bringing the rebated edges of two boards together. One edge of a board may be "grooved," as at j, and the other " tongued," and furnished with a " quirk bead " on the edge, this moulding prevents any opening of the joint, arising from the shrinking of the wood, from being seen; sometimes both edges are beaded,
Another method is shown at I m, the two boards are "grooved," or "ploughed," on their edges, and a separate "tongue" m is driven up the groove thus formed, the tongue m is also called a "slip feather." When the boards are thick two "slip feathers," a, fig. 371, may be used; b b is front elevation, c section. "Dowels" or "pins," as d d, projecting from the edge of one board, and going into holes e e made in the edge of the other board, is another method of joining boards together. The boards f f may also be kept together by cross-pieces at top and bottom, as g g, these being grooved, and the boards at their ends tongued and put together, as at h h i; or the boards may be tenoned, as at j, into the edges k of the boards. To prevent the tenons from shrinking they may be wedged tip, as at l; the mortice being shaped dovetail, as at n, and the wedges m m filling the space up. The boards, as f f, may be enclosed at the sides as well as at the ends, as shown at o p; the usual method of joining at the corners being a "mitre" joint, as at q. In this case the cross-pieces are said to be "clamped." The method of fixing boards together, known as "] edging," has been already illustrated in connection with ledged doors, which see. Boards are said to be " mitre clamped" when the cross-piece, as a a, fig. 372, is finished at one side by a mitre-shaped tenon, which goes into a dovetail shaped mortice c c made in the boards d d a a. If tenons and mortices are used, as in fig. 371 at j, in the case of very thick boards, a double mortice and tenon joint, as already illustrated, may be employed; if the piece to be tenoned, as j, fig. 371, be wide, two tenons may be given to it, as at s, if the thickness of the wood permit of it, in addition to the two tenons, what are called "stump tenons" may be employed, these are short tenons or pins, one on each side of the two principal tenons, these short tenons or pins going into shallow mortices in the other pieces. Fig. 373 shows a method of joining boards together by a dovetailed tenon a, b is section, c front view. Fig. 374 is a more complicated form of joining boards by grooving and tonguing, to which a slip feather a may be added, or the tenon c may have a projection or tongue, as b, going into the groove d; this joint is very secure, but unless the boards are well seasoned, shrinkage is apt to tear the two asunder, and cause an ugly rupture or crack. Another and less complicated method is shown in fig. 375.