Anyone ever see structural channel used for chassis rails (ASTM A-36 for my fellow engineering weenies)? I know it is heavier than rectanglular tubing, but I think it would look kinda cool drilled with some lightening holes...
Channel Iron- 4"x2 1/2" - 13.8 lbs per foot Rectangle tube - 4"x2"x 1/8" - 4.70 lbs per foot Nearly three times the weight. No thanks.
The channel I'm considering at is much lighter: - 3" w/ 1.410" flange weighs 4.1 lbs/ft - 4" w/ 1.584" flange weighs 5.4 lbs/ft This is just a little heavier than the rectangular tubing you mention... Plus they use lots of the stuff at work so it's for me to get my hands on it!
Channel and angle always look out of place. If I need a channel for an X member I get my local sheet metal shop to bend some. As for the frame, the torsional stiffness is much higher with a closed section, which is why channel frames get boxed. So if you can eliminate a step, do it. A look at crossmember vs. X member will show you that you must bend an X member in its stiffer direction to twist a frame while you need only twist a crossmember.
The Jalopy Journal
