KB58 wrote:The problem isn't tube fabrication, it's allowing (easier) access to the entire circumference of every tube when welding. If the head of the TIG/MIG can't be maneuvered into position, it's hard to know whether weld strength is sufficient.
The angle is pretty much the same whether it goes to a node or stops 4" away. Round tube makes it even easier since you can get the torch closer to the center.
It is purely to make those tube lengths less critical. You only have to be close enough to do it how they chose to. If you're only building one chassis, make it perfect and have it go to the node.
Since the Goblin is built with round tube, if the diagonals were made to made to point to the intersection, how would they do that? It would require a specific construction order. And possibly not even possible? I don't care to figure that one out. Someone want to?
Chuck.
“Any suspension will work if you don’t let it.” - Colin Chapman
Often the weld bead that is being covered by the diagonal tube fills most of that space. By the time you round the tips of the ears Kurt described to clear the weld, you can slide them in and there won't be a large gap to fill.
If that fails then it becomes an order of operations - bottom tube first, diagonal second, top tube last.
I know this is an older thread but thought I would reply for anyone who may come in the future.
There is a lot of speculation and no hard engineering ideas not bashing people just saying what I see.
From someone who comes from the American drag racing scene with 1500+ HPstreet legal cars. I would like to point out that as stated by someone else in this thread about FIA in the drag racing world we use SFI standards when building chassis and we use round tubing but the triangulation bars dont need to got all the way to the corner to do there job.
Lots of chassis have bars that dont go all the way to the corners as 1. It's not needed and 2. It makes fabrication more difficult with no real benefit.
Now you dont want it to be miles away from the joint but typically up to 3 inches away ( depending on bar length and size ) is ok.
My 2 cents not looking to argue just putting out the info learned from the drag racing world.
I asked Lonny, the owner and designer of the Goblin, at the Midwest gathering. It is all about access for a solid repeatable weld every time. He agrees its not the best, but he also runs many simulations on his frame designs and its more than adequate. If you to have a thorough discussion with him on it he will most likely be coming to this year's gathering in Harrison AR in May.
He is also working on a whole new frame design based on a different drive train and a off the shelf suspension components from a well known British sports car. (I am not sure what I can say and not at this point)
