I have a big cast iron table saw that has perfectly square edges. I plan to clamp some square aluminum tubing, that I have around from another project, to the table to create a vertical surface. I'm going to build the front triangle flat on top of a full size drawing and then stand it upright to build the rear triangle. This is just a preliminary plan and probably will change as the project moves into the "hands on" stage. I was a mechanic for 30 years before I retired so I "think" better with my hands than with my head!