I hate desk chairs with arms. The arms just get in the way of my arms, me, and end up running into any number of other things. Consequently, I had a bunch of unused desk chair arms taking up space that I needed to do something with, so I made them into a footstool.
I think I may put a cushion or something on it, but it also make a good end table as it is.
I glued together 1x lumber for the top. I have a virtually unlimited supply of medium-quality fir 1×8 from shipping crates at work, so that’s what I used. Add wood glue, clamps, screws, and let set overnight to get a fairly rugged pseudo-plywood. Much less split-prone, as well.
The arms are just screwed in with 1-1/4″ drywall screws with some trusty #10 flat washers. Very handy for holes that screw heads are in danger of fitting through.
I ended up putting four legs on it instead of three, the anti-symmetry of three legs on an octagonal top grated against my sensibilities.
More build photos in the gallery.