Ok. I have figured out how to solve my problem incurred in post: http://www.jalopyjournal.com/forum/showthread.php?t=184446&page=2 I am building a 4-bar set up with bushed radius rods and two upper bars mounted to close to the pumpkin and out and slightly down to pass though, or intersect, with the from pivot point on the radius rod and almost to the center of the front wheels is the imaginary line were to continue. My question is this? Which is stonger structurally, solid round rod or thick walled round pipe? My options for building materials are these, the solid rod being inner driveshafts from torquetube axles and the pipe being heavy stuff from the hardware store. I hope to weld the bushing ends ASAP and get this thing back on the road and see how it should hook up and not break anything. The material needs to hold up under acceleration and braking torque... push and pull.. and hopefully not bend. Thanks. Jonny
I would not use the schedule 40 pipe from the hardware store. I would go to a welding shop and get tubing. I would think it would be the safest bet.
It depends on the dimensions of the rod and tubing. Thanks, Kurt Here's some information: http://en.wikipedia.org/wiki/List_of_area_moments_of_inertia It's the 1st two equations. The larger the number, the more resistance to bending. Basically, you can break it down to which of the radii^4th parts of the equations are larger. There's also an equation for resistance to torque (http://en.wikipedia.org/wiki/Polar_moment_of_inertia).
If you are going to compare a tube and a solid rod made from the SAME material, with the SAME outside diameter, the solid rod will be a little bit stronger or a lot stronger, depending on just how thick wall the tubing is. The comparison you are making is between two unknowns....and neither one is really suitable for the job. Like he said, get the right stuff from a metal supply place.
Wish it wasn't a holiday weekend! I was trying to make due with stuff from around the shop that's collected in corners, etc. You guys are right. The right materials are necessary here, so Tuesday I will be going to the Iron Works to get them. I was getting anxious having taken her out once, I guess. I have plenty to do over the weekend. Jonny
-What he said. Do NOT use waterpipe or gas pipe for any sort of crucial assembly, especially suspension components. It's typically cheap scrap-remelt steel, because it doesn't need more than the most minimal specifications for water or gas plumbing. (I think "it has to be magnetic" is about it, really. ) Now then, for a given diameter, solid rod will be stronger. (Assuming identical materials.) However, for a given weight, tubing will be the stronger. In other words, 1" solid round weighs X and can support Y. But 2" tubing can support about as much, but weighs less. That's why you see roll cages, fabricated A-arms, and radius rods made out of tubing and not solid rod. Save yourself the risk and use proper DOM (drawn over mandrel) tubing. Doc.
Important things for learning to build a safe, reliable hotrod: 1. LEARN PATIENCE! 2. Use the correct materials. In the end, your life and the life of others around you depend on it.
Geee whiz, what kinda of argument is this gonna be if you start throwing out facts like Moments of inertia??? What's next Young's Modulus. This shit keeps up we just might learn something!!!! Serioulsy - thanks for posting that - I hope those who think tubing is stronger than solid will take a close look at what those equations are telling them so that they can make more informed decisions next time.
in my opinion only D.O.M. tubing is an acceptable material for such an application. it is pricey.i just bought some 7/8 o.d. with a .120 wall thickness for my model a and it was about 100 bucks for a 20 ft stick. still a lot cheaper than crashing your ride when the cheap stuff snaps use anything else and you MIGHT... live to regret it.
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