Biscuit Joiners

For particular types of woodworking joints like miter joints, edge-to-edge joints, corner joints, and T-joints, there is no better selection than biscuit joints. Properly cut biscuit joints are accurate and robust, especially for cutting slots with a woodworking tool like a plate joiner (biscuit joiner).

What Are Biscuits?

Biscuits are thin, oval-shaped pieces of compressed wood slivers, generally produced from beech wood. When they’re glued into slots exactly cut with a biscuit cutter, the moisture from the glue leads to the biscuits swelling and tightening the joint. Biscuits are typically available in these three sizes:
  • #0
  • #10
  • #20
A biscuit cutter should be able to cut all three sizes precisely.

Which Size Biscuit Should You Use?

It is best to utilize the largest biscuit size possible since this will offer you the most significant amount of strength to a joint. In most instances, the #20 biscuits must be used; however, working with narrower materials will necessitate switching to a smaller biscuit joiner size.

Edge-To-Edge Joints

This is the most standard type of biscuit joints. They are often utilized for gluing tabletops of different width boards at the equal thickness, where biscuits are used alongside the planed long edges of the boards. To glue a tabletop with several boards, the boards must be laid out side-by-side with each board’s end grain rotated in the opposite direction of the previous board. This will ensure the tabletop is stable when the boards shrink or expand.

Once the board is in the appropriate positions, a pencil can be used to make marks across the joints every four to six inches. These marks will be your centerlines for the biscuit slots. Now, the boards must be separated, and the biscuit joiner adjusted for the right size of the biscuit. In the instance of edge-to-edge joints, you will most probably use the #20 size. Putting the guide fence perpendicular to the edge on top of the stock, the cutting guide must be aligned with the pencil mark.

The fence must be held in place, the saw started up, and once the motor runs at full speed, the blade can be smoothly plunged into the stock until there is no more room to push it farther. Now you can retract the blade wholly and repeat the exercise at the next mark.

As soon as all the slots are cut, a small amount of glue can be placed evenly through the slots on the one edge and the biscuits inserted. Subsequently, apply the same amount of glue in the opposite slots on another edge and connect both the boards. Each edge must be quickly glued up on every edge of the tabletop, and then the entire assembly clamped. Clamps must be snugged to allow all the gaps to close entirely, but be mindful to prevent squeezing too hard that to avoid any glue in the joints being squeezed out. If some glue is coming out of the joints, wipe it off instantly to prevent affecting the finish later on.

Other Biscuit Joints

You can utilize biscuit joinery for various types of joints. The smaller biscuits work effectively for strengthening corner joints and miter joints. Biscuits also work for T-joints, where the end grain of the one board is connected to the side of another board.