Though I would share my build of a tubular cross member. Started with a electrical conduit template. Then bought some 1" gas pipe and cloned the template in a "kinker" After "kinker" Grind off black crap and mock up Weld it in Bitchin weld Etc
Good for you, I always tell people to mock things up with conduit and cardboard just to get things rolling. It also helps if there is a minor oversight, it makes for a cheep fix. Keep us posted. Dashman's Hot Rod & Speed Parts www.dashman.net
Man I love conduit. I make all kinds of trial pieces with it. Nice job on the Fab work. Curious why you chose gas pipe though?
gas pipe doesn`t belong on a car,it`s not made for this kind of thing.....inspect for cracks frequently
x2 on gas pipe..... It's not for structural parts of cars Checking it periodically is a good idea. You may want to bevel your parts before you weld them as well......better weld penetration. Conduit makes great proof of concept material.
I've used conduit to figure out angles & bends before transferring to tubing. Black Iron pipe isn't great for structural or chassis stuff, but I've seen it hold up pretty well on some rock-crawlers exo-cages and a redneck friend built a fart around front engine dragster chassis out of water pipe with a 289 and it held up well. He used to blast down the farm road in front of his house. The first time he took it to the dragstrip they told him he was nuts, so he just plays with it in front of the house and street races other friends. Hell, it's held up for about 10 years with 4500rpm stall and 2-step launches and smoked a 10-second street car. Anyway, as said by others... good ideas and all, not the best material, check it often for any stress cracks near the welds/seams. That stuff shears pretty easily. It might be fine, but if you see a crack in the pipe, invest in some real mild steel tubing and replace it all.
While crossmembers of this style are quite popular I do not understand why. The primary function of a centrally located crossmember , I would think, is to stiffen the chassis, especially in "twist". I do not think this style accomplishes that goal. I believe either an "X" member with a stout center or a "K" style would do more for chassis stiffness in all directions. Somehow the rod shop chassis builders started this tubular style some years ago and it caught on. But, as with many things, what's popular isn't necessarily the best or even good. I commend you on your fabrication efforts, just suggesting your design may not fulfill your expectations, especially with no 'connectors' across the bottom. Ray
Actual tubing... And you may ask yourself what is the difference. Well pipes are used to transport something, and tubes to construct something. Pipe isn't made to be structural while tubing is. Yep... which will be hard to see when it painted a dark color. ^ what he said...
Shoot... black pipe used to be the weapon of choice for bomber stock car fabrication. I've seen whole cages made out of them, heavy but strong if you are a good welder. I liked it for stiffening up bumpers, making rub rails, etc. Not my choice for a chassis piece on a rod, but it should hold up. Bob
Nothing about gas pipe is strong /cracks under stress/will shatter on impact!!!!! Mild steel if cost is issue,chrome molly is made for auto fab
Gday all, This is my first post on this site(great site too..!) and dont want/intend to sound as though i am a know it all, only share my opinion, experience and advice if possible. The main difference between pipe and tube is the wall thickness and where/how it is measured, outside diameter and inside diameter respectively. I am guessing what is meant by 'gas' pipe is the same as what we call 'steam' pipe in australia.? If so, he wouldnt have too much of a problem with using that product where he has. minimal flex etc. There are certainly different types of both products and placement specific, ie chrome moly in light weight/high strength suspension components. It wasnt that long ago chassis builders/handymen made kit cars etc out of light walled square and rectangular tube and sand all the smooth/flat. I would keep an eye on any fabricated part as the material can fail from a fault if not seamless tube/pipe etc as well as poor workmanship. FTRUKK
As is mentioned above by several people, gas pipe (schedule 40) is not structural. I commend your rescourcefulness but you could probably break that assembly on a decent pothole and drop the trans out the bottom. CREW,(cold rolled electrically welded) tubing is about the minimum for crossmembers. This type of assembly works well as pioneered by TCI and Pete and Jakes if constructed of the right stuff. A lot of risk here to save a few bucks. You could have had two pieces of 10 Ga. oiled and pickled braked to fab a '39 style X member for less cash than the cost of the water pipe and not run the risk of disaster. It's just not worth it! In my opinion, not that anybody actually listens, cut this thing out and do it right. PM me if you like and I'll gladly talk you through a safer crossmember. As I mentioned though, good creativity! I'm not knocking your work, I've just seen too much of this stuff fail. I like everybody coming home in one piece.
I made my k member (at least I think it's a k member) out of some spare 2x3 and the shock mount piece from a Merc Monterey. It's pretty stiff..
Henry had his "X" member start up around the rear of engine, come together to form the "X" , and extend to rails near the start of the up-sweep at the rear. Your "H" member seems quite a bit shorter and too far apart to get the most additional stiffness to be gained by the installation. It would not have taken much more material to start closer to the front and extend closer together in the center. This would better duplicate Henry's engineering and purpose of an "X" member. Just my thoughts on the deal.
I'll add this thought. The purpose of an 'x' member is to eliminate, or at least reduce, the potential for the frame to change from a square/rectangle into a parallelogram. The front and rear crossmembers usually are not sufficient in size to resist the induced forces when the vehicle is under power and the right rear tire is trying to catch the front tire. The ideal 'x' member would actually connect to each opposite corner but ideal doesn't work well in a chassis. Take a look at the size/placement of the 'x' member in a '40 ford (just one of many examples...) and you can see what the designers thought they needed for a 100hp car... Dreddybear's example is simple and should prove to be very rigid. You might follow his lead. .
This is a k x as I call it,I like your frame but the flex will be in the middle,Which is ok ,Most frame builders build it your way.
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