Paragraph 73. The tongue and groove joint is very commonly used in joining the edges of boards. This joint is found in all kinds of flooring and ceiling. It is also used somewhat in joining boards in cabinet construction, such as in table tops, counter tops and in other places where wide boards are needed. It is not common to prepare a tongue and groove joint in the shop; material is usually purchased with the tongue and the groove already made; this is particularly true in flooring and ceiling. While the tongue and groove joint is not commonly made by hand, yet there are frequently occasions where it is necessary to do a little of this kind of work. For this reason the shop should be provided with a set of matching planes for the purpose of cutting the tongue and groove. One plane is so constructed as to cut the tongue while the other is formed to cut the groove (these planes are sometimes so constructed that the same plane does the work of both, one side being used for the tongue and the opposite side for the groove work). To Prepare Tongue And Grove.

First, see that your material is planed perfectly straight and square on the edges. Then place the material in the vise exactly as though you were going to plane the edge, and with the matching plane (which must be firmly held against the working face) plane a groove (B) on one edge of each piece of material. Plane a tongue (A) on the opposite edge of each piece. This joint can be assembled with glue or treated as the nature of the work may demand.