When the tenon comes through the beam, it is secured from drawing by a pin or peg put through it.
The Dovetail is used to secure one beam into another, when they have to resist any strain acting so as to draw them asunder, rather than to carry any weight; it is consequently employed to frame wall-plates, or the timber laid in walls to carry the ends of beams of floors, roofs, and so on, which plates tend to bind the walls together as well as to receive the ends of the beams. The term is derived from the end of one beam being cut into a shape resembling the spreading tail of a bird, which is pinned down in a corresponding wedge-shaped recess cut in the other beam to receive it. It is clear from this construction that no force, acting in the direction of its length, could pull the first beam out of the second without breaking off the dovetail, which the tenacity of wood-fibre renders nearly impracticable in one of any size. The dovetail is extensively used in all cabinet-making, and may be seen in almost any mahogany or deal-box.
When two beams of equal thickness are required to cross one another and to lie in the same plane, they are halved together; that is, a notch is cut in each of half the thickness of the other, then the uncut part of each lies in the notch of the other respectively, and the two are pinned together.
Distinction between Carpentry and Joinery.
The smaller and better kind of work executed by the carpenter is called Joiner’s work, such as the making of doors, windows, stairs, wainscotting, boxes, tables, &c. &c., which are usually formed of yellow or Norway deals, wainscot, or mahogany.
When a large surface is to be of wood, it is not formed of planks fixed together side by side till the requisite width is attained, but it is formed of framing and panelling. A frame-work of the area required to be covered, is formed of narrow planks, with cross-bars between to strengthen the frame; these are called stiles and rails, according to the directions in which they run, the former name being given to the upright planks of the frame, while the horizontal ones are called rails.
The rails are mortised into the stiles, and the tenons, since they must be comparatively thin, are made proportionably wide, nearly as wide as the rail. The tenons are always pinned into the mortise holes by one or two wooden pins driven quite through the stiles and through the inclosed tenon.
The edges of the stiles and rails are ploughed, that is, a rectangular furrow is cut in the edge by means of a plane, to receive the ends and sides of the panels. These panels are formed of thinner deals than the stiles and rails, and are made by glueing the edges of two or more boards together to make the proper width of the panel; the ends and edges of the panel are thinned off to fit into the groove or furrow in the stiles and rails, or else the ends and sides of the panel are rebated, that is, worked by a plane into the form shown in the following figure, the projecting part being received into the furrow.
As the panels are thinner than the frame, the former constitute so many recesses, at least on one side of the framing; and a small moulding is glued round the edge of the panel to form a finish to the work. Or else the same object is attained by working the edge of the stiles and rails with such a moulding, so that when the panel is put in, the moulding may finish against it. Sometimes the face of the panel is made to lie in the same plane with the face of the stiles and rails, and the panel is then said to be flush, and the edges of the stiles, &c., are finished with a small bead, also flush with the panel when finished.