I'm looking to build my first torsion box for my CNC router. The dimensions will be 48"x48". I'm planning on using a 4" rib width for a total 5" thick torsion box. I'm going to use 1/2" MDF for the skins but was wondering about using 1/2" particle board for the ribs. I have a sheet of it already and would like to use it up. To me it seems like it would be strong enough when turned on end but I'm concerned about attaching it to the skins. Even a finishing nail will split it when hammered to the end. Has anyone used PB for their ribs before? What was your experience?
I would recommend ply for the skins it is more stable over time and much more robust as you fasten and remove things on it mdf or particle board will do for the ribs but glue it won't nail if you screw, remove the screws you don't want any metal, especially steel, where a bit may hit it please use a spoilboard but be careful with fasteners a screw thru the spoil oars that hits a screw or nail in the top skin won't drive true my spoilboard is mdf with t nuts on a 3 inch grid pattern for hold downs has worked well for 12 years it's about time to replace as I am getting close to exposing the t nuts hope this helps
Dave