As I mentioned in the "What do you use to design" thread (or whatever it was called), I like to do mockups in cheap materials, sometimes affectionately known as Cardboard Aided Design. I enjoyed my drafting class in high school where I did some by hand and most in the last release of AutoCAD before it got 3D functionality. Most of my work has been in digital imaging, with a few years in construction as well, and my 2D work in Photoshop, Illustrator, Lightroom, QuarkXPress, and InDesign seem to be blocking me from getting my head around 3D design. As a result I find it easier to just mock up with cheap, easy to process materials rather than fight with the software that just isn't doing what I want. I'll get there, but I'm not there yet. My brother-in-law uses a lot of MDF, especially melamine-faced, in his cabinet business, so I am often able to get scraps. At one point he had a stack of a couple hundred pieces of 3/16" melamine at about 18"x48" each after a massive commercial cabinet job. I won't need to go get more any time soon, as I took a couple dozen pieces home. The beauty of this is that it is the same thickness as the hundreds of pounds of scrap A36 flat stock I have from a shop where I worked. I also have 1/2", 1", 1.5", and 2" square tubing scraps. It's very easy to make up those sizes from 1/2" and 3/4" plywood and 3/8", 1/2", 3/4", and 1" MDF scraps. When I have some scraps of those that are too small to be very useful for other things I rip them into strips that match the steel scraps I have. Then when I need it to mock up a project I don't have to set up the table saw, I just quickly cut the previously prepared "stock" to length at the miter saw. Here's my first draft of my 2"x72" belt grinder: (The dowel section represents the gas shock I'm using for belt tension, at full extension.) Some of what is solid here actually represents tubing. Note how well they correspond: I try to do this to actual dimensions I will be using in the final build so I can just reference from this for all my cuts and layout later. I even have one corner of the base plate here designated as "Reference", with every dimension from that corner a nice easily repeatable fraction. Mind you this is the actual build currently in progress: I learned enough from the mockup to change my mind about most of the design. Then I was confident enough to proceed without doing another mockup. I don't know if this will help anyone, but hopefully it will get some ideas started/planted for a few others.