Fig. 289. The Way a Mitered Joint Opens on Account of Shrinkage.
In window sashes, the dovetail joint, Fig. 267, No. [47], is the common one at the upper end of the lower sash and the lower end of the upper sash, and the mortise-and-tenon joint modified is used at the lower end of the lower and upper end of the upper sash. The glass takes the place of the panel. In blind sashes, the pinned mortise-and-tenon joint, Fig. 267, No. [38], is commonly used.
When panels are joined together to enclose a space, then we have what is properly called cabinet construction. Illustrations are cabinets, bureaus, desks, lockers, chests, etc.
In all these cases, the constructed panels may be treated as separate boards and joined together with dowel pins or splines or dadoed together without any other framework, tho the corners are often reinforced by cleats or blocks glued into them. Sometimes, however, as in chests, Fig. 290, posts are used instead of stiles, and rails are mortised or doweled into them and the panels set into grooves in both posts and rails. In this case the bottom is raised from the floor, and may be dadoed into the bottom rails, or dowelled into them or even supported by strips attached along their lower inside edges. The chest really is a union of both paneled and framed structures.
Fig. 290. Chest Construction.
(4) FRAMED STRUCTURES
The principle of the framed structure is similar to that of the panel construction in that the object is to allow for shrinkage without harm to construction and also to economize materials. Common examples are tables, chairs, work-benches, and frame houses.