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Discussion Starter #1
ok got the green light to budget for the rhino(89 grey bronco with one of prerunner style bumpers that looks kinda like a horn from profileview).
First stage will be the rollcage(safety first)decided to go with 2" .120 wall square. I went with the square as it supposedly stronger and didn't want to be just like every elses round tubing :thumbup that and this will be easier to bolt onto. stage (1a)moick up, found some thick L channel card board at work almost perfect mockup material. ram steel is chargeing $60 for a 20' stick is there a better price out there help me out oregon crew:toothless got the carboard all squared up and relized it was 3:00 not enough time before work to do any actual mock up inside the bronc besides my two year old buggered off with my tape measure (wonderful little buttheads lol) suggestions, plans and opinions always welcome and ill keep you posted as we go
 

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I think most people use round tubing for a reason. I'm not 100% but I believe it is stronger in more directions than the square stock. I hope someone else chimes in with info on this too.
 

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I believe there is a reason they use dom or hrew. the strongest part of square tube is the corners and they make up the least amount of surface area on the material. hrew or dom would be a better chioce if ur goal is safety first, because it is round on all sides( sounds gay i know) and has an inhierent advantage over square in that a thinner piece of dom is substancially stronger than the same thickness and over all size of square tube. in most cases hrew is a good choice for cages in the rigs that most of us would build. with a tensile strength of 60,000+ psi ( using good usa tubing) we most likely never roll or crash at speeds that would exceed that kind of strength.
 

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Discussion Starter #7
:whiteflago ok ok i surrender good thing i didn't buy the steel yet just thought i would try some thing new. but if the round is truly stronger my concern for the fam safety is more important then my need to be different. Talked to the senior operator (hes the guy that engineered a lot of custom pieces at work) and decided to run both floor plates on the outer edge nearest the body,and a floor bar and mount to the frame through the body to this bar any thoughts?
 

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Do some research before atemting it, if you still question your self I say you should go with a kit from JBG or somewhere similar. When it comes to roll cages and safety there is no room to reinvent the wheel.
 

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:whiteflago ok ok i surrender good thing i didn't buy the steel yet just thought i would try some thing new. but if the round is truly stronger my concern for the fam safety is more important then my need to be different. Talked to the senior operator (hes the guy that engineered a lot of custom pieces at work) and decided to run both floor plates on the outer edge nearest the body,and a floor bar and mount to the frame through the body to this bar any thoughts?
Glad you switched to round. MUCH needed decision:thumbup\

As for the above - if I am reading your post right it sounds like you want to do a "sandwich plate." Meaning, the roll cage will land on a flat plat that sits on the floor in the cage (make this BIG like 4" x 4" MINIMUM to spread the load) and then another matching plate below the floor that has a tube welded to the bottom of it that goes to the frame. These plate would be about .125" thick and bolted together - through the floor pan - right??

If so - yes this can work.

If you are not welding the roll cage to the body and are keeping rubber or polyerethene body mounts then I would strongly suggest using a poly bushing where the cage hits the frame rather than welding the cage tubes to the frame (or bolting them solid).
 

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:whiteflago ok ok i surrender good thing i didn't buy the steel yet just thought i would try some thing new. but if the round is truly stronger my concern for the fam safety is more important then my need to be different. Talked to the senior operator (hes the guy that engineered a lot of custom pieces at work) and decided to run both floor plates on the outer edge nearest the body,and a floor bar and mount to the frame through the body to this bar any thoughts?
Start here...;)

http://www.fullsizebronco.com/forum/showthread.php?t=44417&highlight=roll+cage
 

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Discussion Starter #11
thanks for the link up good ideas only issue is this is a daily runner and an family sand cruiser alot of these cages are great for other rigs but mine still needs some creature comforts. also i saw afew rigs just running the front cab area protected witha small extention to cover the back seats but leav the back some what open. by the way thanks again for steering me from square damn sales guy is supposedly a engineering student whatever :goodfinge
 

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most common cages are made from 1.75x .120 wall tubing and its fairly low priced as meterial is constantly going up. here locally i can get 16-24' sticks at just over 2.00 a foot not bad when its delivered. i think u made the best choice in staying away from square tube, though i have seen it used in small areas where round tube wouldnt work, and as long as its tied in and braced properly i dont see any problem using it when saving a little space is needed when packing a family and gear for a day trip or a weekend.
 

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Keep us updated on everything you are doing with your cage. I am gonna start mine soon, if I am able to keep my rig running more than broke down
 

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please include pics and such...My 89 bronco sounds like similar purpose as yours and I am also in the beginning stage of gathering material and design ideas... and yes, the DOM tubing is the way to go =) ... anyways, good luck and I look fwd to hearing and seeing your progress
 

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best advice i have is to spend a lot of time looking at race cars and see how they do stuff and copy as much as you can. also look for as many pictures of rolled vehicles as you can find, and see what failed, what didn't, what from the factory is actually stronger than most think etc..

good things: minimal bends, short tubes, triangulation, spreading of load, tubes making a node where an impact is likely to occur, sandwich plates like chasetruck mentioned, welding the cage to the body and then making the cage attach to the frame with bushings

bad things: welding the cage directly to the body and then to the frame, bends where an impact is likely to occur, long unsupported sections of tube, lack of triangulation, inadequate load surface where the cage goes through the floor, SQUARE TOOB, making it too close to your dome etc.

basically, don't copy my cage is there is a lot of no nos in it.
 

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You do not want your "sandwich" plates to be the same size as each other either as this will create a shear effect and tear thru your body.
 

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You do not want your "sandwich" plates to be the same size as each other either as this will create a shear effect and tear thru your body.
POSSIBLY - and over a long time. It totally depends on how the cage is built (sandwich plates on bottom have a tube tieing down into frame - or not, cage tied into body in other locations, rubber, poly or aluminum "body mounts", etc.) and size of sandwich plates. As I said - bigger is better. 4" x 4" is alright and 6" x 6" is even better. The larger plate distributes the load over a larger area of the body/sheetmetal and will make for less stress on the sheet metal.


How come you cant weld it directly to the frame? I understand why you dont wanna weld directly to the body. But why not the frame?

Ford frames are tempered and the heat of welding screws with the heat treat or tempering the factory puts in the frame (allowing them to flex) and therefore makes the frame more brittle in the heat affected zone.

That being said some people have welded on the frame and have run the trucks for years without major issue.

Would I do it - no, but that's me. I think welding something directly to the frame is the easy/lazy way out. I make plates that bolt to the frame and the parts, cage tubes or whatever get welded to that.
 

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How come you cant weld it directly to the frame? I understand why you dont wanna weld directly to the body. But why not the frame?
What he is getting at is you can't weld to both because the moves on the frame and will break something.
 
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