How to Make Wood Biscuit Joints

There are many joints from which to choose, but the biscuit joint is the one selected most often for its strength and accuracy. Biscuits work well on T-joints, miter joints, corner joints and edge-to-edge joints. The biscuit joiner (plate joiner) is the woodworking tool that cuts the slots for the biscuits.

Difficulty: Challenging

Instructions

Things You'll Need:

• Safety glasses
• Pencil
• Biscuit joiner
• Biscuits
• Wood glue
• Clamps
• Cloth

1. Decide what type of joint you are making and pick the appropriate size biscuit. The #20 biscuit will work in most cases, but for thinner material, the smaller one is the best choice.

2. Set the biscuit joiner's depth adjustment to the size biscuit you have chosen. The height adjustment is set to position the biscuit in the center of the stock. If you use double biscuits for each joint make certain to leave at least a 3/16-inch space between the biscuit and the edge of the board and between the biscuits.

3. Place the boards in the proper position for the joint chosen and mark the location for the slit with a pencil line.

4. Make the cuts with the biscuit joiner. Pressing the tool against the wood causes the 4-inch blade to emerge and releasing pressure causes the blade to retract. Hold the fencing guide in place perpendicular to the edge of the board and align the cutting guide with the pencil mark. Smoothly plunge the blade into the stock until it will not go any further then retract it completely. Continue until completing all of the slots.

5. Apply a small amount of glue in the slots on one side and insert the biscuits then repeat on the opposite side. Connect the two pieces and clamp them together to allow the glue to dry. Avoid clamping so tight that all of the glue squeezes out of the joints. Wipe off any excess glue with a damp cloth before it dries.

Tips & Warnings

• Biscuits come in three sizes: #0, #10 and #20. Use the largest biscuit possible to provide more strength to the joint.
• To prevent humidity from damaging biscuits store them in a dry, airtight container.
• Fit the pieces together in the dry before gluing to ensure there is a proper fit.
• For stock thicker than 1-inch, double biscuits at each location may be necessary.
• The biscuit joiner blade needs replacing if it burns or smokes the wood while cutting the slots.