@ ambrose, screw fasteners on uprights were the original idea. Then thinking the screws might muck up the sides of the strongback. Considering using craft store axle pegs instead - still kicking myself for not drilling the holes before assembly.
@pompano,thanks for the tip about sanding. Since it seems you’ve done this type of glue up, did you (or anybody else) get much spring back of the foam?
Yes! plywood would have been much better (and probably cheaper) - for the whole thing - as none of the dimensional lumber had square edges. I had to rip one side of the three 1x2s used inside the strongback to square it up. Did pick out two decent 1x10s and glued them up with opposing rings, so hope it stays true.
Skip all the drilling and stick with your clamps. If it ain’t broke… your slots would have to have front-back play as well as up & down, that’s the hardest thing about rocker tables: as rocker flattens, your table elongates too. I love the clamps & friction fit, I think you solved a big problem by going backwards. Well done.
I’d maybe take a hole saw and blow some round holes through the strongback so you can poke bar clamps through to grab the legs from almost anywhere. Then you could add a base to the strongback as well and not worry about how you were going to clamp. But definitely skip the drilling, slots, and hardware. Its brilliant, as it is.
I agree with Paul about some triangular gussets on the legs.
if you use a pu glue, it will not slip. It also will be a pain to sand through. If you can see your blank shape in the layers (think 3D) before you glue, you can get close to not having to sand through it with proper glue strategy. I’ve done tests on some of the other eps compatible glues and they can slip in shear. Bottom line for me was I learned how to shape with the pu glued blanks and then bought a large block of 1 lb. eps and hotwire my blanks now.
I attached a pic of my first rocker table. Cheap and dirty.