It fastens and holds the ends together at the bottom.

It separates and supports drawers.

It is used vertically as divisions when solid partitions are not required.

Skeleton frames are assembled before being installed in the case. Dowels, biscuit joint, or mortise-and-tenon joints are recommended joints used to make a skeleton frame.

ENDS. - The case ends are made of solid edge-glued lumber or plywood. They may also be paneled frame with stiles and rails and plywood or hardboard panels. Paneled ends are made similar to paneled doors using either doweled or mortise- and-tenon joints.

The back edge is usually rabbeted to receive the cabinet back. If the case is to be fitted to the wall, the rabbet is cut deep to recess the back and allow the projecting material to be scribed to the wall.

The front edge is joined to the face frame with a butt, rabbeted, or mitered joint. If a butt joint is used, the front stile of the case end is made narrower than the back stile because of the thickness of the face frame.

Case ends may also be dadoed to receive the top, bottom, fixed shelves, skeleton frame, and dust panels of the case.

LEGS. - Sometimes the stiles of the case ends extend below the bottom and act as legs. The front stiles of the ends also act as a stile for the front frame. In this type of construction, it is usual for the skeleton frame to be notched around the leg. It then extends to the front and becomes the face frame and dividing rails for the drawers.

PARTITIONS AND SLEEPERS. - Partitions are vertical members dividing the interior of the case into sec- tions. They tie the top and the bottom of the case together and are usually dadoed into the top and bottom. The skeleton frame, dust panels, and shelves are cut in be- tween the partitions and are usually dadoed into the partitions. Partitions are also known as divisions or standards.

Sleepers extend from the bottom of the case to the floor and are located directly under the partitions. They provide support of the case to the floor and keep the bottom from sagging.

SHELVES. - Shelves must be strong enough to support the weight placed on them. They must also be wide enough and correctly spaced for their intended purpose. Shelves may be made of solid wood, plywood, particle board, or glass.

Bookcase shelves should be from 8 to 10 inches wide and spaced 10 to 14 inches apart. The length of a 3/4-inch-thick shelf should be no more than 36 to 42 inches without intermediate supports. Supports should be spaced close enough to keep shelves from sagging under the weight placed upon them.

One way of increasing the strength of a shelf is by installing strongbacks. A strongback is a strip of wood screwed on the edge to the underside of the shelf. It is placed either on or near the front or back edge of the shelf or both edges of the shelf.

Fixed shelves are usually dadoed in or supported on wood cleats (fig. 5-6). A cleat is a small strip of wood

Figure 5-6. - Fixed shelf construction.