Tongue and Groove Joints

In the drawing is shown the method of jointing by the process known as grooving and tonguing. The tongue and groove method is resorted to for joining boards, of any required length, along their edges; such as are required for the back-boarding necessary in such pieces of furniture as bookcases, cupboards, and the like, in which it is not prominently shown. It may, however, be used, when cleanly dressed and beaded (as indicated in the picture), for the exposed backing of any large piece of furniture, such as in the upper or dresser portion of the sideboard illustrated in Plates XX. and XXI in the sideboard hutch plans. In this case the boarding should be of the same wood as the rest of the work.

In grooving and tonguing in the manner shown in the picture above, special match planes are required. These planes go in pairs, one forming the tongue, by cutting away, to a fixed extent, the wood on each side of it, and the other sinking the groove to receive the tongue.

It is usual to give such match-boarding a neat appearance by beading one edge of each board adjoining its tongue, as indicated in the illustration : this is done with a bead-plane. When match-boarding is not in a position to be seen, it is unnecessary to bead it.

In the accompanying illustration, below, is shown another method of forming a joint by the process of grooving and tonguing, which differs somewhat from that previously described and illustrated. In this method both the pieces that are to be joined are grooved in the manner indicated at A and B, while the tongue is formed of a separate piece of wood, dressed to the thickness and width necessary to tightly fit into, and completely fill up, both the grooves, but allowing the joint to be brought absolutely close in the process of gluing. This tongue is shown at C. The tongue is indicated with its grain running longitudinally; but when the joint is not a very long one, and great strength is required, it is advisable to use a tongue with its grain in the transverse direction : it may also be desirable to make it of some very tough hard wood, such as oak or ash. In sinking the grooves the plane called the plough will be required.

Tongue and Groove Joint

When the joint is to be completed, very hot glue (not very thick) must be used ; and the boards should be pressed together between clamps until dry. Care must be taken to see that the boards go together perfectly flat with respect to each other.