How to Make Wood Lap Joints

Wood lap joints are made by laying 2 pieces of wood overlapping one another. The main elements for good lap joints are the pieces of lumber used for making the joint. Both the pieces must be similar and must overlap each other. This technique is used for creating furniture, toys and construction framing.

There are 2 types of lap joints, the full lap joint and the half lap joint. One of the simplest wood joint is a half-lap joint. This is a joint where one half of the thickness of the connecting wood surface is removed and fixed to the other surface using screws or adhesive. Half lap joint proves to be the perfect choice to join 2 stock pieces. These joints are used in the construction of timber frames. Making a wood lap joint is not an easy task, as it requires some carpentry skills and patience. Here we make a half lap joint. Usually in a half lap joint, 2 pieces of wood are connected tightly to each other at right angles.

Step Number 1: Checking for Uniform Thickness of the Boards

A planer is used to make the thickness of the wooden boards even. To make a wood lap joint, you need 2 wooden boards of the same thickness. Run the wood through a planer. It strips off material from the surface of the wood. Measure the board and ensure that the width and thickness of both the boards are same.

Step Number 2: Marking the Board

Measure the width of the board from the end and use a marker to mark a shoulder line. The shoulder line indicates the length of the cut from its end to the edge of the joint.

Step Number 3: Adjusting the Saw Blade

Set the blade depth of the circular saw blade to half the thickness of the board. Use this to cut on the shoulder line that is drawn already.

Step Number 4: Cutting the Board

Now, use the saw to make a series of closely space cuts at every 1/8 of an inch from the shoulder line back to the end of the board. Use the hammer to knock out all the waste wood.

Step Number 5: Smoothing the Surface

Next, use a chisel and scrape the surface smooth, to remove the remaining waste wood. Notice the bevel ends of the chisel. Ensure that the bevel ends of the chisel point downwards, to prevent it from digging into the wood. It does not take that long to get a pretty smooth surface. Repeat this process at the corners and diagonals as well, to get a perfect joint.

Step Number 6: Joining the Boards

Once both the boards are cut in the similar manner, create a tight interlocking joint by overlapping the boards. You can either glue or screw the boards firmly in place. The shoulders of the joint will support the weight. You have successfully made a lap joint.

Precaution

Wear gloves to protect direct contact with sharp edges of wood, blades, etc., and eye wear for protecting your eyes from any physical damage.