I ran by the salvage yard today. They didn't have 1/4" thick flat stock in 2.5" width, and I didn't want to be making a bunch of long cuts down the length of the stock, so I took 3/8" instead. I figure the extra 1/8" won't hurt anything. Maybe a little extra weight. For the torsion bar, I got a 2" piece of square stock, 1/8" thickness. Everything smaller was gauge thickness, so it was an easy choice, since I won't stick weld thinner than 1/8".
They didn't have DOM tubing for the bushings. I found some tubes with about 1 1/16" ID and about 1/8" or 3/16" wall thickness. I am pretty sure that is not going to work, but I didn't want to leave empty handed, so I bought it anyway.
Here's my current question: with regard to the bushings, what maximum clearance is desirable relative to the diameter of the pins. The pins are 1" exactly. That gives them as much as 1/16" of slop with the tubing I bought today (that probably isn't going to work). What should I be shooting for? 1/16"? 1/32"? Should I basically buy 1" ID tubing and somehow ream it out just enough to accept the pin? I measured the existing tubes and they are exactly 1" ID. The existing pins are exactly 1" diameter. So, clearly, the tolerance between the pin and the tubes is tighter than my chintzy little caliper can measure. Not sure how I can machine this to work, unless through some stroke of luck, the pins are actually slightly under 1", and a 1" ID piece of DOM tubing will accept them. I dunno. Without a piece of tubing in front of me, I'm not sure how to answer the question.
Sadly, it also looks like I am going to have to source actual DOM tubing, because I don't think I'm going to find anything sufficiently thick-walled to make things work off-the-shelf.
I also don't think there's anyway 1/8"-3/16" wall thickness is strong enough. The factory tubes are 1/4", just like the side plates.