If you need adjustable shelves it is easy to drill a series of holes in the sides to receive short pieces of dowel stick on which the shelf can rest as shown in Fig. 13h. Also there are available simple screw-on shelf-supporting brackets, as shown in Fig. 13i, or metal brackets that fit into holes drilled in the sides. However, these two devices make a less secure shelf than the other methods described.
Table and Counter Tops
Another simple and common operation is that of attaching table or counter tops. Here, too, you can choose from a variety of methods. The vertical board under the edge of a top is called an apron, and usually it is fairly narrow. It serves to stiffen the top, besides adding to the appearance, and therefore should be firmly attached to it throughout its length.
The simplest way of joining the apron and top is to nail through the top down into the edge of the apron. But this is not usually recommended. In Fig. 14 you can see five ways of attaching an apron by countersinking screws into the bottom edge of the apron (Fig. 14a); by recessing the screws in the inside face of the apron (Fig. 14b); by cutting a groove in the apron that engages with either a wood or metal clip screwed to the top board (Fig. 14c and d); and by using metal angles (Fig. 14e).
In many such joints it pays to use what are known as glueblocks, as shown in Fig. 15. These are simple blocks of wood, preferably of a hardwood such as sycamore or maple, made to fit into the angle between the two surfaces to be joined. The two adjoining faces of the block are well glued. The block is then laid in position and rubbed back and forth an inch or so in the angle. This works the glue into both surfaces. The block is then left in place for the glue to set. If the piece is upright or must be moved, you can use a finishing nail to hold the block, or even clamp it, while the glue is drying. This should be avoided where possible since it may pull the block slightly away from one surface.