A biscuit joiner, sometimes known as a plate joiner, is a woodworking tool that allows you to make special joints like edge-to-edge joints, t-joints, miter joints and corner joints in your woodworking projects. It has a circular saw that will cut to the proper depth and shape into the side of a piece of wood to allow your biscuit to fit. A biscuit is a thin, oval-shaped piece of wood, often 1/8th of an inch thick (lengths vary) and made with compressed beech wood shavings.
Biscuits tend to be glued into slots that are cut precisely using a biscuit cutter. The moisture that comes from the glue will cause the biscuit to become swollen, which will tighten the joint up. Biscuits are used to strengthen a wide variety of different joints, making wood-working projects more sturdy in the process.
If you're planning a new woodworking project, you may have to contemplate which biscuit joiner size you will need to get the job done. A biscuit joiner can be used to connect two pieces of wood together without the use of nails and screws. Biscuits look a bit like a football, and many of them have grids on the top and bottom to hold the glue securely in place.
For installation, a hole is cut into both pieces of wood that is the right size for the biscuit in play. After a bit of glue, the biscuit can be inserted into the slots and will hold the two pieces together after it expands within the wood. This is great for creating a seamless look with your woodworking pieces.
If you are wondering which biscuit joiner size will be right for your project, consider the explanations below for a breakdown. Note that all biscuit joiners are 5/32 inch thick, so the only thing changing here is the width of the oval.
Small Biscuit Joiners - #0
#0 biscuit joiners are 1 3/4 inch long and 5/8 inch tall. The smallest of the sizes, this model can be used for connecting smaller pieces of wood or in areas where there isn't a lot of anticipated stress. Stress will break these little biscuit joiners quite easily, so it is best to leave that part up to wider models. Picture frames often feature this size joiner because of their lack of stress and small wooden pieces. These biscuits work well in narrow settings as well, like if you need to put a frame around a kitchen cabinet door.
Medium Biscuit Joiners - #10
#10 biscuit joiners are 2 1/8 inch long and 3/4 inch tall. They are the fall back pieces for just about any project, being not too big or too small. They are great for various framing projects, and if your local hardware store only contains one type of biscuit joiner, you can bet that this will be it.
Large Biscuit Joiners - #20
#20 biscuit joiners are 2 3/8 inch long and a full 1 inch tall. These are made for projects where a lot of twisting or weight will come into play. Unlike the options above, these joiners work well with plywood and particleboard, which usually can't be joined without a great deal of hassle. The benefit of using such a large biscuit is that you have a bigger space to apply glue to and you have a stronger hold inside. Sometimes these joiners are just too big for the task at hand, however.
Choosing the Right Size
If you are having difficulty selecting the right sized joiner for your project, go with a smaller option and see how it holds up. You can always cut a bigger hole for a bigger biscuit. It's hard to work when you do things the other way around. Make sure that you only apply glue to your biscuits right before insertion because they will expand on contact. That's what gives them their hold in the first place.
Faces and Frames
The “face” is a common woodworking term for the clean and smooth front side of your wooden project. It is most often used to refer to things like the front frame on a cabinet box, where hinges and/or latches are installed. Biscuits are used to join the face to the box because it doesn’t require nails, screws, or anything else that will show up to the naked eye later.
The face frame is made up of a combination of stiles and rails. Stiles are the vertical pieces to the frame, while the rails are the horizontal pieces.
Measure And Cut
Measure out and cut each piece that you plan to assemble using your biscuits. Typically, if there is also some nail, screw, and glue work to be done, you’ll want to do this now. And if you are building a face for any sort of cabinet, be sure to take your measurements for the face from the front of your constructed cabinet box.
Lay It Out
Take each piece that you plan to biscuit join together and lay them out on a flat surface exactly as they should look when you’re done. First, this helps to make sure that you’ve cut everything to the right sizes. Also, you’ll need to use a pencil and tape measure to mark the center point at each connecting point where you’ll be using a biscuit. Be sure to mark the same spot on both pieces.
Applying a Biscuit Joiner
Read all the instructions that come with the biscuit joiner. Your joiner should have a center indicator; line this up with your pencil mark, and plunge cut the blade into the edge of the joint.
Check Your Cuts
Place dry biscuits into each of your cuts and fit the whole frame together. This is to be sure that the cuts were made to the right size, and to make sure that everything fits to the right measurement. Be sure to measure diagonally from corner to corner. If you come out with one diagonal longer than the other, make minor adjustments until they are equal.
Apply glue to the joint cut. Then, lightly brush glue on each biscuit, front and back. Place the biscuit into the cut, and fit the wood together. As you are fitting pieces together, use a clamp to hold each piece firmly in place while the glue dries. Lay a spare piece of lumber between your face piece and the clamp to keep the clamp from leaving any marks.
After each piece has been glued, and the glue has been allowed to dry over night, your biscuit joiner work should be done!