A rebate, or lap joint, is a way to join two pieces of wood. It is common in the building of furniture, cabinetry and other speciality woodworking projects. Cutting a rebate joint is simple, providing you have the proper tools and the know-how.
Examine your timber and mark your cutlines. Make sure your timber is straight. It is important to work with satisfactory material. After you've selected a suitable piece of wood, mark out where your cut will be on the end of the board. For the strongest joint, cuts should be between 1/3 to 1/2-inch into the thickness of the timber. Set your marking gauge to the desired thickness and pencil a line across the end of the board and down the edge about 1/2-inch. This will be your first cutline and determine where the second line will be. For your second cutline, lay the piece of wood flat, with the first line facing away from you. Use a combination square to extend the first line down the edge 1/3 to 1/2 inch and across the face of the board. The face can also be drawn with a scrap piece of wood of the same width.
Make your cuts. Using a circular or tenon saw, make your first cut across the face of the board. To make the second cut, secure the board in a vice so you can safely cut along the end. If are not skilled with a circular saw, use a tenon saw to create your joint.
Chisel out and smooth the joint. After you've made your cuts, use a wood chisel and hammer to create the trench of your joint. This must be done carefully. Be sure to take your time. After you have removed the scrap, smooth the area of the joint. If you are working with a large enough piece of wood that will accommodate the use of a hand planer, lightly plane away the rough spots. Do not use too much force with your planer. If a planer will not work, use sand paper. When finished, your trench should be ready for a flat board to fit into it.
Repeat the above steps for a double joint. A rebate joint may also contain two pieces of timber, both containing trenches. If you wish to create a double joint, the trench on the second piece of timber can be formed using the same process. Once finished the two pieces will fit together with one board standing on its end and the other face down joining the first trench.
Be sure you measure depth correctly.
Always wear safety glasses.