Using biscuit joinery:
One of the projects I've been working on recently is a bathroom vanity.
The case is made of cherry veneer over a hardwood plywood core. Because it is made of plywood I decided to use biscuits for the joinery.
Biscuit joinery is a good choice when you are using sheet goods such as plywood or MDF. It is quick and all the joinery is hidden so it leaves clean lines.
Biscuits aren't as strong as mortise and tenon or dovetails, so they aren't suitable for everything. But in this case biscuit joinery is plenty strong.
The nice thing about using biscuits is that you can cut all the pieces to final size without worrying about adding or subtracting for the joinery. Instead, the main thing with biscuits is to make sure that you have the same reference surface for each cut.
Biscuit jointers work by making matching slots in two joining pieces of wood. The only important thing is to make sure those slots line up. The way to do that is to mark your lines carefully and to use the same part of the biscuit jointer for reference.
I used the bottom of the jointer for reference. In other words, the bottom of the tool determined the height of the slot.
Most biscuit jointers have a way of adjusting the height of the slot that it cuts. On my jointer I can either raise the bed of the jointer, or lower a top piece and lock it into place at any angle I like. It doesn’t matter which way you line up your slots, just make sure you stick with the one you’ve chosen.
The other thing I do is make myself a story stick. On a single project like this one it is less important, but it’s a good habit to get into. I take a piece of scrap the same width as the case and layout the biscuits on the scrap. Then I use that to make sure all my slots are the same distance apart on each piece.
If I don’t do that, I have to number each piece to
make sure it lines up with its mate. For instance, if I'm making
something with 5 shelves, I don't want to have to make sure that shelf 1
goes in the bottom, shelf 2 next, etc. I'd rather be able to grab any
shelf and have it fit. So, I use my story stick to get the spacing the
same on everything.
I then clamp matching
piece together in such a way that I can cut the slots in both at the
same time. I use my story stick to lay out the marks for the slots and
I’m ready to cut. I cut a slot into the end of the piece with the
biscuit jointer vertical, then I cut the face of the matching piece with
the jointer horizontal.