In a framed cabinet, a number of construction techniques can be used to hold the box square and rigid. The choice of methods and materials used go a long way in determining the quality of the box. The cabinet sides are usually dadoed into the face frame and rabbeted into the back. I-beams along the sides (or struts front and back) are best dadoed into the face frame, cabinet side, and cabinet back. In addition to or instead of I-beams, you may see corner blocks. Wood corner blocks are stronger than plastic or metal ones. In box materials, look for 1/2" plywood sides and at least a 3/8" plywood back. The face frame should be made of solid wood.

The sides of a frameless cabinet box support most of the weight. ¾” plywood is considered the optimal box material for frameless construction. Thinner boxes are not as strong. The box may be constructed of MDF or plywood. Plywood has better water resistance, accepts screws better, and hinges and slides are easier to adjust or repair in plywood. The box parts of a well-built frameless cabinet are usually held together with wooden dowels and glue. Closer spacing of the dowels indicates better construction, and wooden dowels are stronger than nylon dowels. The dowels hold the box square. Other joinery methods include Confirmat screws (a thick screw something like a dowel), or clips. The back may be slightly dadoed into the cabinet sides (a captured back) for increased rigidity. A stretcher across the front completes the box. Sometimes there are stretchers both front and back, or a completely covered top.

There are 2 main types of cabinets, framed and frameless.

Shown without doors or drawers you can see the obvious difference, which is the face frame. There's a lot more holding framed cabinets together, which is why framed cabinets are generally stronger than frameless.

Frameless construction is a European method of building a cabinet box. There is no face frame to hold the box square, so the box is normally made of thicker plywood or MDF than an equivalent framed cabinet, and construction has to be more exact. Doors hinges are attached directly to the box. Framed cabinets (right) have a face frame holding the box together. Door hinges attach to the face frame.

The horizontal members of a face frame are called rails and the vertical pieces are called stiles. Usually they are 1 1/2" wide, cover the front edges of the box, and are made of solid wood. Some cheap framed cabinets have a vertical divider where the doors meet in a double door cabinet. Everybody dislikes them because the stile prevents full cabinet access. If you see a center stile on a cabinet 36" wide or less, it's an indicator of poor quality. In cabinets wider than 36" the center stile is needed even in good quality cabinets to help keep the frame square.

In a framed cabinet, a number of construction techniques can be used to hold the box square and rigid. The choice of methods and materials used go a long way in determining the quality of the box. The cabinet sides are usually dadoed into the face frame and rabbeted into the back. I-beams along the sides (or struts front and back) are best dadoed into the face frame, cabinet side, and cabinet back. In addition to or instead of I-beams, you may see corner blocks. Wood corner blocks are stronger than plastic or metal ones. In box materials, look for 1/2" plywood sides and at least a 3/8" plywood back. The face frame should be made of solid wood.

The sides of a frameless cabinet box support most of the weight. ¾” plywood is considered the optimal box material for frameless construction. Thinner boxes are not as strong. The box may be constructed of MDF or plywood. Plywood has better water resistance, accepts screws better, and hinges and slides are easier to adjust or repair in plywood. The box parts of a well-built frameless cabinet are usually held together with wooden dowels and glue. Closer spacing of the dowels indicates better construction, and wooden dowels are stronger than nylon dowels. The dowels hold the box square. Other joinery methods include Confirmat screws (a thick screw something like a dowel), or clips. The back may be slightly dadoed into the cabinet sides (a captured back) for increased rigidity. A stretcher across the front completes the box. Sometimes there are stretchers both front and back, or a completely covered top.

There are 2 main types of cabinets, framed and frameless.

Shown without doors or drawers you can see the obvious difference, which is the face frame. There's a lot more holding framed cabinets together, which is why framed cabinets are generally stronger than frameless.