Because biscuit joints are easy to mark out and quick to cut, using one almost seems like cheating. The safest way to cut biscuit slots is with a biscuit joiner. The oversized slot lets the biscuit move slightly, enabling you to tweak parts into perfect alignment.
Biscuits come in different sizes, but #10 size biscuits and #20 size biscuits are used most. When laying out the biscuits, simply place them on the stock to see how many are a good fit for the joint and to make sure there is at least a half inch from each edge, remembering the biscuit slots will be slightly larger than the biscuits. Check out the video above for a step-by-step walk through of how we join carcase miters with biscuits at the Center for Furniture Craftsmanship.
“The slot for a #0 biscuit measures about 21⁄8” wide, so you can’t hide a biscuit joint in stock narrower than this. Even a well-tuned biscuit joiner can sometimes cut slots that result in a non-flush-fitting joint. Cutting the spline slots on your tablesaw requires a tall jig, but you can cut them easily and quickly with your biscuit joiner and the attached fence jig, see drawing below.
how to biscuit a miter joint Related Question:
Can you biscuit joint a 45 degree angle?
Mark the center lines for each biscuit to align with the biscuit joiner. Most biscuit joiners have a variety of fence positions; on a 45-degree miter, the fence should be on the 45-degree setting. After test cuts, it is a very fast operation!
What makes a biscuit joint so strong?
They are more for alignment, where the dowels will add a good deal of strength. In my use of biscuits they are designed to keep joints from pulling apart. The clearances the cutter makes to insert the biscuit allows for enough movement that alignment is not guaranteed.
What are the disadvantages of a biscuit joint?
Biscuit joints do not stand up well against other joinery methods. We won’t spend any time comparing with mortise and tenon joints because all other joinery methods pale in comparison when measuring strength. But, as an example, the use of dowels as opposed to biscuits is a step up in strength.
Can you biscuit joint a Mitre?
face miters A few biscuits can solve both problems. They can register the ends so that the corners can’t slip during clamp-up and strengthen the otherwise end-grain joint. A biscuit-reinforced miter is as strong as a full table saw-cut spline, but biscuits can be hidden within the miter for a cleaner-looking joint.
How far apart do you put biscuit joints?
Biscuit Spacing Once you’ve determined the positions for the edge biscuits, you can calculate even spacing for the biscuits between the edges. Anywhere from 6 to 12 inches apart, measured on-center is usually sufficient.
Are biscuit joiners worth it?
They will definitely provide more strength than glue alone, but not a lot. If your boards are too narrow, you can reinforce the joint by adding the biscuit on the back side of the face. But again, I would prefer to just use pocket screws, dados, or rabbets.
How long do biscuit joints take to dry?
In the right conditions a glue joint can be dry enough to take movement and light handling (no more than this!) in 20-30 minutes but when it’s cooler this could take an hour or longer.
What are jointing biscuits?
A biscuit jointer, sometimes referred to as a biscuit joiner, cuts notches in both pieces of wood you wish to join, into which you insert and glue a biscuit. The resultant joints are strong and reliable, preventing any lateral movement in your workpiece.
Which is stronger dowels or pocket holes?
The dowel joints were 1.5x stronger than the pocket hole joints. I could have made the dowel joints stronger by using four dowels instead of two. Earlier tests indicate that such a joint should be nearly as strong as a mortise and tenon joint.
Are biscuits supposed to be tight?
Biscuits should be somewhat loose; they are not designed to align parts. They are compressed during manufacture and are designed to swell with the application of water-based adhesive. Good quality biscuits should actually rattle just a bit in the slots.