Shop Talk

The "How To" of March 2012

  • How to Produce a Better Biscuit Joint:


    10 Tips for More Effective Biscuit Joinery


    Because it produces a flush and surprisingly strong joint, biscuit joinery is becoming one of the most common methods of wood joinery in the woodworking industry. Despite the relative simplicity of the process, though, there are a few trade tricks that will ensure your joinery process and subsequent biscuit joints are more efficient and professional. Incorporate the following ten tips and fast become a better biscuit joiner.

    Better Biscuit Joinery Begins With These 10 Tips:

    1. Before You Cut, Test-Cut

    Of course, practice makes every performance more polished and while it’s good to accumulate experience, it is also important to remain humble in the face of your project; it is important to practice and analyze a cut before pouncing directly upon your workpiece. Accordingly, you should perform a test-cut in a scrap section of your working material. This allows you to gather a better feeling for your workpiece and presents an opportunity to plop a biscuit in that practice slot. This ensures you won’t encounter any surprises, jaw-droppers or knee-slappers when you engage the actual workpiece.

    2. Dig a Little Deeper

    To allow a little room for your biscuit to grow on and to ensure your workpieces can come together perfectly flush, cut your biscuit slots approximately 1/32nds of an inch deeper than half of the width of their corresponding biscuit. Do this on both workpieces to ensure a clean fit, a clean joint, and a spot of extra space for your biscuit to swell in.

    3. Bigger Biscuits are Better

    As a rule, where a joint has greater gluing surface area, the stronger that joint will be. Accordingly, when determining which biscuit size you should employ for your project, the largest biscuit that will fit is usually the best biscuit to use. Incorporating the most biscuit unfailingly results in a stronger wood joint. Despite that fact, though, it is important to appropriately down-size your biscuit when working more narrow or more delicate projects.

    4. One is the Loneliest Number

    If the workpieces being joined are or are greater than one-inch in thickness, use two biscuits (rather than one single biscuit) at each slot. This enhances the strength of the joint allowing it to better withstand the force of the workpieces being joined; preserve the resilience of the joint with a companion biscuit.

    5. Biscuit Bandages:

    Despite both experience and perfectionism, some mistakes are inevitable. Accordingly, there are a few impending errors looming in any crafter’s biscuit joinery future. Don’t fear these blunders, though, because a biscuit can also be a bandage. If you mis-cut a slot, simply glue in a biscuit, allow it to set, and trim it flush with the edge of your workpiece. This allows you a second chance (or even a third or fourth chance) to get that slot in the right place.

    6. Facial Recognition

    When cutting slots into adjoining boards, it is crucial that you cut each piece with the same face facing you. In other words, to ensure your slots will align and that your workpieces will come together flush, if you cut slots in one piece with the front face facing towards you, you must also cut the second piece with its front face facing towards you. Otherwise, you’ll almost certainly encounter a sciwompus joint.

    7. Dump the Dust

    Empty your dust bag often; this ensures a happier tool and cleaner, more accurate cuts. Of course, your dust collection system should always be engaged while cutting and you should always keep yourself protected with safety glasses and a face mask. Dust collection and a clean work environment are key elements to a high-functioning tool and an efficient work shop.

    8. Trial Run

    Before you go ahead and squeeze your own weight in glue onto your project, it is a good idea to put all the pieces together dry. Pre-assembling your joints (before applying any wood glue) allows you to ensure that all points are matching up as they should. Assemble the joints dry before gluing them down to establish that all edges are flush and that all slots are aligned.

    9. Make the Most of Your Wiggle Room

    Because the biscuit slot is a bit larger than the biscuit itself, after you’ve glued and assembled a joint (but before the glue sets the joint), you should have a bit of wiggle room. As such, this joining technique is one of life’s only methods that grants a little leeway; use it to your advantage. If your joint isn’t sitting exactly flush or is in one small way or another misaligned, push it around a little bit. The additional elbow room should allow you to maneuver and clamp the joint into a more desirable position.

    10. Respect the Blade

    The circular saw blade in your biscuit or plate joiner does a lot of work. Carving biscuit slots is a dirty enterprise and, accordingly, this blade can get a little dirty, too. To ensure the smoothest slot cutting and a longer life for your blade, keep the blade clean. Carefully and frequently wipe the blade and treat it to a little WD-40 after a long day. Additionally, although I want to promote a good, lasting relationship between you and your blade, if it becomes too warn to perform or begins to burn your workpieces, you should invest in a new one.

    Altogether, and especially with these few tips, biscuit joinery is a rewarding practice that allows woodworkers to easily produce a strong, accurate wood joint. Apply these tips to your joining process and you’ll create a better joint for it.