Dear James: Our ugly old kitchen cabinets are falling apart, so I want to try to make my own. What are the best wood joint designs to use so they hold up better?—Chris P.
Dear Chris: Making your own kitchen cabinets is a great project in which you can express your own individuality and personality. Even if you have to go out and buy some new woodworking tools for this project, you will definitely save money compared to buying new kitchen cabinets.
Using the proper joint designs is critical to making high-quality, durable cabinets. The easiest method to recognize a homemade cabinet is by the joinery. First-time cabinetmakers often use simple butt joints and, to make it worse, they generally do not even fit well. Butt joints can be strong, though, if they are assembled with dowels.
The keys to a professional-looking project are selecting the proper type of joint for each piece and using high-quality wood. If you use inexpensive wood, no matter how much time you spend finishing it, it will never look good.
First, plan the entire project, including the types of joints that you plan to use for each piece. For a quality cabinet, you will probably use three or four different types of joints for different pieces. Once you decide on the types of joints you want, you will know which hand and power tools you need.
Miter joints will be one of the more common joints that you use in any project. The two pieces to be joined are usually cut at 45 degrees. The purpose of this joint type is to hide the end grain of the two pieces of wood, and it is usually fastened together with nails, screws or adhesive. It is a relatively weak joint, so it is often used for trim pieces.
Most miter joints are 90-degree angles, so an inexpensive miter box and hand saw are adequate. If you are planning joints other than 90 degrees, you should invest in a power miter saw which allows adjustments from 0 to 45 degrees. The angle that you cut is always half of the finished angle. For example, to make a right angle, each piece is cut at 45 degrees.
Lap joints, where one piece rests in a notch in the other piece, are much stronger and not too difficult to make. A full lap joint is used when pieces of different thicknesses are going to be assembled. The thicker piece is notched to the full depth of the thinner piece to create a flush joint surface.
When using pieces of the same thickness, which you will be doing in most cases, use a half lap joint. Each piece is notched to only half its thickness. Use your common sense to determine if the thickness of the two pieces is different enough to warrant a half or full lap joint.
A variation on the lap joint is a dovetail lap. It is more difficult to fit properly, but it is an excellent joint where the two pieces are in tension. The lap notch in one piece is cut with a taper on it. The other piece has a reverse taper to interlock into it.
You will probably use rabbet joints for the shelves and floor of your cabinet. The joint is formed by cutting a recess (rabbet) into one piece. The width of the rabbet should be the same as the thickness of the mating piece. Its depth is typically half the thickness of the piece. Dado joints are similar, but the recess is cut across the grain.
