You can use 1/2" plywood for the whole thing webbing & cover. If you can get 3/8" plywood it would work fine for the covers top & bottom if you can get it. The important thing it to be able to pull the sheeting down tight to the webbing with glue & fasteners . Screws work best because they work like clamps. Start in the middle & work out toward the edges. Remember we aren't getting any younger & things just seem to get heavier. The idea of a torsion box is to make it flat strong & light.
Also If you use 1/2" webbing & can still get like 7/16" or even 3/8" for the covers it will be very strong but much lighter.
I don't think I'd make the webbing more than 1 1/2"- 2" deep. I actually think 1 1/2" webbing with 3/8" plywood covers would be fine for an assembly table. You would end up approximately 2 1/4" thick over all. It should be plenty strong with glue & screws yet still light & easy to move.
The important thing is to set up a flat place to work. You can rip & joint some material. What I used was so 2x4 material that I had on the shelf that was very dry. I ran it through the table saw & jointed it & the set it up on saw horses & shimmed it until the 3 2x's were absolutely flat across the tops of all three & screwed them to the saw horses with a piece of plywood screwed down to the 2x’s.
Then I laid out a grid on the outside of the plywood torsion box covers centered on where the webbing would be on the inside of the box & drilled & countersunk holes in it Then I laid out the sides & ends with lines & pre drilled & counter sunk holes where the ends of the webbing should align I put the box sides together & laid the webbing together inside it on top of the temporary table with glue & air nails at the joints in the webbing & then went around & shot the screws home around the sides & put the glue on top of the webbing I laid the top sheet on squared it up & started in the middle screwing it down. Then just flip the box over & put the other side on.
I would make 2 panels 2' wide & what ever length will work for you. You can always place them next to each other. Make some way to lock the 2 panels together nice & flat. I want to have a system like this with legs out of interlocking plywood when I have a shop that is big enough.
This is my CMS multi tool cabinet with the torsion box base. My friend & I jumped up & down on on the box when it was first mounted on wheels no give at all.
I hope this helps
Last edited by Bart Leetch; 03-01-2007 at 01:40 AM.
"Forget the flat stuff slap something on the spinny thing and lets go, we're burning daylight" Bart Leetch
"If it ain't round you may be a knuckle dragger""Turners drag their nuckles too, they just do it at a higher RPM"Bart