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This is probably over thinking it. But in a hard roll, what are that chances that the b Pillar could fold to the rear at the harness bar? Would you see a strength gain tieing that into the c pillar?
 

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Discussion Starter #42
This is probably over thinking it. But in a hard roll, what are that chances that the b Pillar could fold to the rear at the harness bar? Would you see a strength gain tieing that into the c pillar?
Absolutely zero. Probably less than a bent tube (read compromised diameter) in its place with no other connecting nodes. Not to mention, the entire "X" behind the seat would have to collapse for that B pillar tube to fail. You must remember that any cage is an engineered system that is bound by every node in said system, connecting all the load paths. (exactly why there should be no dead nodes in a cage design.)

That said, there will be plate work that ties the harness bar to the Motobilt shock plate on the high line inner fenders, with a frame tie in under the fender, along wih a seat countoured door bar going forward to node at front seat tab bar.

Oddly enough, this has been a topic on every forum I have this build on, along with phone calls. Google- trophy truck chassis, Goatbuilt, top ultra4 team chassis such as Miller Motorsports; and take note of all the miters and open tube nodes versus bent tubes in the entire chassis. And I did this on the comanche in a number of spots- yet I didn't recieve near the questions of why...

Goatbuilt, how many bent tubes are seen here versus miters...




miller chassis; very few bends, many mitered joint- including the entire subframe, and open tube (capped end construction)







kinetik trophy trucks- near zero bent tubes





I'm no engineer (officially, but i did begin a college career at NC State for such- life happened and i didn't complete), but I recognize sound design when I see it.

Any pros want to add tech here please feel free! I'm always willing to learn more!



I hope this doesn't come across as defensive, because I certainly do not intend it to be. I enjoy the questions and I try to be versed in my techniques and do the research for why I chose so. This is a tech forum. :D.......and someone better educated could change my mind.

matt

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The layout of the tubes is sound, I don't really see an issue there. My only concern is with a crushed or torn tube from compression or tension. An easy fix is an aluminum slug/end cap and gussets at the intersections.

My entire A to C pillar is one continuous piece with zero junctions or splices. B pillar comes down and there are multiple triangulated pieces. I think I have one or two "dead" tubes but they're gusseted and have redundant tubes to reinforce the area.

Maybe I missed it, but I didn't think this was a racecar and all of these situations where the tube would fail are based on an absolute destruction of the rig - which is highly unlikely and very different than a trail flop or roll. My two cents anyway.
 

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Discussion Starter #44
The layout of the tubes is sound, I don't really see an issue there. My only concern is with a crushed or torn tube from compression or tension. An easy fix is an aluminum slug/end cap and gussets at the intersections.

My entire A to C pillar is one continuous piece with zero junctions or splices. B pillar comes down and there are multiple triangulated pieces. I think I have one or two "dead" tubes but they're gusseted and have redundant tubes to reinforce the area.

Maybe I missed it, but I didn't think this was a racecar and all of these situations where the tube would fail are based on an absolute destruction of the rig - which is highly unlikely and very different than a trail flop or roll. My two cents anyway.
correct, trail rig only.

It will be capped very similar to miller's car above, and many places on the manche.

once it's all together, there will be no question.

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My concern was non of the above( miter joints, or weld nodes, tear out, etc). I was questioning if you were to push straight down on the b pillar, would it fold to the rear(like into the fenderwell). I realize that would require drastice deformation of the other bars. I would have the same concern with a bent one piece tube.

As to all the other cars listed, like Millers, etc. They have door bars connecting those node, x bars, etc.


I realize that your cage isnt done Matt, just thinking aloud as each design i see, I try to learn the how, why, and future performance of it. Great work as always, glad to see the thread is getting updated!
 

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My concern was non of the above( miter joints, or weld nodes, tear out, etc). I was questioning if you were to push straight down on the b pillar, would it fold to the rear(like into the fenderwell). I realize that would require drastice deformation of the other bars. I would have the same concern with a bent one piece tube.

As to all the other cars listed, like Millers, etc. They have door bars connecting those node, x bars, etc.


I realize that your cage isnt done Matt, just thinking aloud as each design i see, I try to learn the how, why, and future performance of it. Great work as always, glad to see the thread is getting updated!
If you were to just take the B-pillar and push vertically down on top, there would be both vertical and horizontal forces at that junction. So, yes it would cause the bar to push to the rear. But with bracing to the rear, like Matt is planning and other tubes connecting the node, it should handle more than the forces it could see. If the cage had no more tubes in it, it would still likely be ok for a trail rig, but with a few more tubes (as planned) in the chassis the strength will increase exponentially.

The reason for all the mitered joints might just be a simple one......ease of manufacturing.
I would agree with this. They can draw the chassis up in CAD and send it to be CNC cut and arrive on a pallet. Esp if you are talking about using thick wall tubing.

But they wouldnt be using this tradeoff if it wasnt found to be as strong or strong than bent tubes.
 

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If you were to just take the B-pillar and push vertically down on top, there would be both vertical and horizontal forces at that junction. So, yes it would cause the bar to push to the rear. But with bracing to the rear, like Matt is planning and other tubes connecting the node, it should handle more than the forces it could see. If the cage had no more tubes in it, it would still likely be ok for a trail rig, but with a few more tubes (as planned) in the chassis the strength will increase exponentially.
.
Right, this was my question if there will be a connecting tube?
 

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I think people are beating a dead horse. Tube work is not nearly complete and once done it's not moving. Matt's work is pretty damn legit. ;)
 

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But they wouldnt be using this tradeoff if it wasnt found to be as strong or strong than bent tubes.
That's the catch 22 with mitered joints. I can go out a make a dozen 90* bends with my model 4 and they will all be the same strength. Make a dozen mitered joints, and it comes down to the guy who welded them together.
 

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I think people are beating a dead horse. Tube work is not nearly complete and once done it's not moving. Matt's work is pretty damn legit. ;)
I want to be CLEAR, my question was by no means a criticism to Matt's work, purely curiosity on how that design would fair as-is, under a hard roll, since it is a design that I am not familiar with and a bent b pillar is new to me without supporting tubes.


Carry on Matt, it's good stuff. :smokin:
 

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Discussion Starter #53
I want to be CLEAR, my question was by no means a criticism to Matt's work, purely curiosity on how that design would fair as-is, under a hard roll, since it is a design that I am not familiar with and a bent b pillar is new to me without supporting tubes.


Carry on Matt, it's good stuff. :smokin:
Not a problem. I never took it as anything other than just that. This is a tech forum, I have zero issues with any questions asked and answered by anyone!

This style joint plays into my wheelhouse better. Especially working alone. I can do most of the tacking on the bench at the proper angle, then I place the upside down 'u' on the base tubing; strapped in the center to the dash bar; then I build the upper b post to the roof bar while I can adjust the angle of the lower half u to get the pitch I want.

Personally, I don't enjoy bending tube anyway; you'd have a hard time finding any build of mine that had a tube with more than one bend in it. And this is easier in my mind than a bent b post, and getting the clocking of the notches correct to get the correct angles in that post in the forward profile. It's a plus, that when properly done it's as strong or stronger than bending tube.

Remember, I'm a self taught (over 20 years now) hack, and it's a daily struggle to make things easier for working alone. One way I intend to make this struggle easier; I'll be purchasing a Certiflat weld table and fixturing tools here soon...I have a straight axle ultra 4 car to build starting this summer for an east coast guy....... now if I just had a plasma table...

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Not a problem. I never took it as anything other than just that. This is a tech forum, I have zero issues with any questions asked and answered by anyone!

This style joint plays into my wheelhouse better. Especially working alone. I can do most of the tacking on the bench at the proper angle, then I place the upside down 'u' on the base tubing; strapped in the center to the dash bar; then I build the upper b post to the roof bar while I can adjust the angle of the lower half u to get the pitch I want.

Personally, I don't enjoy bending tube anyway; you'd have a hard time finding any build of mine that had a tube with more than one bend in it. And this is easier in my mind than a bent b post, and getting the clocking of the notches correct to get the correct angles in that post in the forward profile. It's a plus, that when properly done it's as strong or stronger than bending tube.

Remember, I'm a self taught (over 20 years now) hack, and it's a daily struggle to make things easier for working alone. One way I intend to make this struggle easier; I'll be purchasing a Certiflat weld table and fixturing tools here soon...I have a straight axle ultra 4 car to build starting this summer for an east coast guy....... now if I just had a plasma table...

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I designed and built this table for my shop, hands down my favorite and most used tool. Before I built it I was thinking about just a certiflat top and I would build my own frame, looking back now I'm glad I didn't because I use the holes on the side of the table all the time


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Discussion Starter #55
I designed and built this table for my shop, hands down my favorite and most used tool. Before I built it I was thinking about just a certiflat top and I would build my own frame, looking back now I'm glad I didn't because I use the holes on the side of the table all the time


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That's the style I will purchase. Along with some of their fab squares and table wings.






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I see it as just another fab style. Mitered/few bends seems to be "The style" these days. I bend tube and notch because I can and I like the look better. Just another way to skin a cat...
 

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Discussion Starter #57
I see it as just another fab style. Mitered/few bends seems to be "The style" these days. I bend tube and notch because I can and I like the look better. Just another way to skin a cat...
That's right!

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Discussion Starter #60
I love the lines of this thing. It’s very obvious where you pull your inspiration from :D


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Hard to beat classic buggy lines like Jim's garage, m&m, Campbell, Goatbuilt, Jesse Haines, etc etc...

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