“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 use biscuit joiner Related Question:
Are biscuit joiners worth it?
Biscuits joints serve best as a quick and easy way to keep glue-up parts in alignment, and that they add appreciable pull-apart to strength joints that would be otherwise too weak to stand on their own – like butt joints and miter joints.
Can you use a biscuit joiner on plywood?
However, with a biscuit joiner, clean, unobtrusive joints can be made in plywood, with no visible hardware and clean edges coming together. Whether joined together at 0 degrees, 45 degrees or 90 degrees, all joints are clean and tight, as well as being strong.