The Basics of Biscuit Joinery

If you're a new woodworker then the chances are good that you've heard the term "biscuit joint" but had visions of grandma baking up a piping hot tray of buttermilk biscuits. You're on the right track if you're thinking "a method for joining two pieces of wood," because that's precisely what a biscuit joint is. Not only that, it's one of the simplest methods of true joinery and a great place for beginning woodworkers to get started with learning the basics.

1) What Is A Biscuit?
A biscuit is a thin, ovular piece of compressed wood - typically birch. They are remarkably strong because they're constructed with a diagonal grain pattern, meaning they're tough along the length and the width. Biscuits are also designed to be porous. Biscuits come in three sizes: the #0, which is 5/8" x 1-3/4"; the #10, which is 3/4" x 2-1/8"; the #20, which is 1" x 2-3/8".

2) How Does The Biscuit Work?
Biscuits are the connecting pieces between the two pieces of wood you're seeking to join - think of them as the dowels in a dowel joint. But in a biscuit joint you're cutting holes in your pieces that are more like trenches, made to accept the biscuit as a toaster accepts a piece of bread. Once you glue your biscuit in it absorbs the water in the glue and expands, making your joints rock solid.

3) What Are The Best Applications For The Biscuit Joint?
There are woodworkers who use biscuit joints whenever possible. Your professionals and extreme hobbyists tend to use them primarily when joining panels, corners, miters, face frames and T-joints. If you're just getting started then be sure to pick a very simple application - try just an edge-to-edge joint and see how it goes for you before you launch into any new projects.

4) Why The Biscuit Joint?
Many woodworkers swear by biscuit joints because they are so much faster than traditional methods for joining wood. Further, it's one of the best joining methods for new woodworkers seeking to go beyond the standard butt joint, or who are tired of their glued joints always breaking on their projects.

5) What are the Required Tools and Accessories?
Biscuit joining requires you to purchase biscuits plus either a biscuit joiner (they're also called plate joiners) or an appropriate add-on for your router. Typically the biscuit joiner itself is going to give you an easier out-of-the-box experience with less fussing with set up. It will be more expensive though and if you're on a tight budget then look for something that will work with your router. Also you will need a good supply of the wood glue of your choice.

6) Biscuit Joining Tips
Here are a number of tips to help you on your way as you begin using biscuit joints in your projects.

a) Cut each slot 1/32 of an inch deeper than half of the width of your biscuit on both boards. This ensures a clean and even fit for your biscuit.
b) Cut a practice slot in scrap wood before cutting into your working piece. Test your biscuit in the practice slot so that you're sure that your cuts are accurate.
c) Assemble your biscuit joints in a dry run before you glue up. This will help you see if you're missing anything or are misaligned in any way on your project. And you definitely want to know this before you've got the glue out.
d) Biscuit joiners are notoriously bad on dust collection. Empty the dust bag frequently and make sure that you're wearing your face mask and have your dust collection filtration system working over time while cutting the biscuit slots.
e) If you're having trouble picking which size biscuit to use on your project, pick the biggest that fits. When joining you want as much biscuit in your project as possible to ensure a strong joint.
f) If your stock is one inch thick or more you should use two biscuits. This is a general rule of thumb that doesn't apply in all circumstances.
g) If you mess up cutting your slot just add a biscuit, glue it and then trim it to the edge of your board. Then just recut the board in the right place.
h) Your joiner blade can collect just as much gunk as your saw blades. Keep your WD-40 handy for cleaning the blade off and always replace the blade if it starts to burn your wood.

7) What Are You Waiting For? Get In The Shop And Start Joining!
Now you know the basics of biscuit joinery and have an arsenal of tips to help you along on your next project. It's time for you to research and choose your biscuit joiner and start getting what no article in the world can give you - biscuit joining experience. Good luck, have fun, and most of all... BE SAFE!