This is a quick basic direction for how to make a very rudimentary, and quick, Plywood shelf. I made this at Techshop SF using the table saw, dado stack, band saw and belt sander. In all reality if you have the table saw with a dado blade, you will be fine.
I used 3/4 inch prefinished ply that I found in the scrap bin, so really anything big enough, and strong enough to make your shelf will work.
Step 1: Cut Sides
First step is to cut your side pieces to the right length and width.
I took the extra step of rounding off the top front corners with the belt sander just for aesthetics, but this is by no means necessary.
Set the fence on the table saw to your desired width and rip away, when cutting the sides to length, I used the cross cut sled, but you could use the band saw as well, or just be super super careful. If you are not comfortable and knowledgeable cross cutting on a table saw, I highly recommend using the sled to save yourself stress and potential injury.
Step 2: Select Your Wood
Find some wood. This step is likely the most important, without materials, you aint making anyting.
Step 3: Cut Shelves to Size
Next up, cut your shelve pieces to size. I used 4 shelves because thats what I had wood for, and because I needed taller shelves, but you obviously can do whatever works for your needs.
Again, if you are cross cutting, either use the sled or the band saw unless you know your stuff.
Step 4: Istall the Dado Stack on the Table Saw
If you are using your own tools, install the dado stack. Make sure to measure the actual (dont trust what it says it is) thickness of your wood and use whatever shims, etc needed to make the dado stack cut the exact same thickness. If you are at a TechShop location, ask for a DC to install the stack and work with them to get the sizing spot on.
The closer the tolerance the stronger and more stable the shelf.
Lastly, set the dado depth to no more than half the thickness of your side pieces, you dont want the shelf to collapse because a side split and broke.
Step 5: Measure and Cut the Slots for the Shelves Into Your Side Pieces.
So the way this works is that each shelf is going to sit in a dado cut slot on each side and get screwed in. Measure out the where the cuts need to go, to space the shelves the way you want.
Using the cross cut sled and dado blade, cut the slots paying attention to cut them on the facing sides of your side pieces (this only matters if you have rounded the corners on the front or otherwise distinguished one end from the other on your side pieces)
NOTE!!!: I always test cut a slot and check it with my shelve pieces to make sure the fit is as I want.
Step 6: Assemble Your Shelves and Screw in Place
Just like it says, slide the shelves into their corresponding slots and screw in place.
Step 7: Optional Corner Brace
Just to make my shelf a bit sturdier, I cut small wedges and braced the top and bottom corners of the shelf unit. This may be necessary if your slots were too wide or the shelf is otherwise wobbly, this is a quick easy shelf, not an amazing heirloom piece after all.
Step 8: Enjoy Your Shelf
Well now that all your (hard) work is done, enjoy your shelf and pat yourself on the back.