UPDATE
I am building drawers with an inside dimension of roughly 15.5" wide by about 26" deep.
There are three different drawer heights; roughly 4", 7", and 10" tall.
My initial intent was to make all of the drawer bottoms from 1/2" plywood, but, for the 4" tall drawer, is 1/4" likely to be sufficiently thick?
Ok -- update...
I made a box that fits under the top of my table saw's right extension's insert. The insert is "hinged" so I can swing it up to get access to the box. I store ZCI's and featherboards and other small table saw stuff in it.
The box is 1/2" thick MDF and is 4.5" high x 25" x 12" - nearly the same size as Andrew's 3" deep drawer.
For the bottom I used a piece of 1/4" (borg) birch ply.
It's - ok - not great but ok.
I'd feel better about it if it was 3/8" or 1/2" - which I would have used except for the fact that the scrap MDF I used for the sides was only 4.75" wide & I didn't want to sacrifice the extra 1/4".
I plan to add a 1/4" brace across the bottom @ the midpoint.
"Life is what happens to you while you're busy making other plans." - John Lennon