Outer Limits 4x4 Board

is this gonna be stong enough braced up? I'm using box cuz I don't have access to a pipe bender. People have told me 2mm box is a strong as 3mm tube, any one shed any light? thanx

The main problem I can see is that you have all these sharp angles instead of radioused curves. I'd try to borrow a bender from someone or even hire one from a hire tool shop. If your ever thinking about going in a comp, even a nav comp. then do it right the first time. You don't want to be guessing about safety items on the vehicle and you will never get passed scrutineering. You also have to cover the bar with padding anywhere you can bang your body on it. Will be difficult with a square tube.

round is much stronger, somthing to do with the radius of the tube?
square will deform very easly, too many flat edges ect....

Snarba wrote:is this gonna be stong enough braced up? I'm using box cuz I don't have access to a pipe bender. People have told me 2mm box is a strong as 3mm tube, any one shed any light? thanx

No it isnt. Due to the flat sides, box will deform on the sides very easily under load and cause the whole section to ultimately collapse. The strength in box is in the corners, this is where all the load is concentrated. In tube, the load is evenly distributed throughout the section so load is dissipated through the tube.

Also, when fabricated, with a tube/tube welded joint, the load is spread into 1/2 the diameter of the tube being welded on to, whereas for box, the load is being borne by one side only (very weak with 2mm box) sure it can be gusseted, but that will add lots of hack metal to somehting already ugly, and if it is not done properly, it won't add the strength where you need it.

Box is not suitable for structural work when it comes to occupant safety. that's why there is no form of motorsport that will allow square tube for occupant protection.

tube is also stronger by weight - i.e for box to to be as strong as tube, it will weigh WAY more for the same length. This is also why tube is used over box in motorsport.

Tube benders can be hired from hire shops, or a bending company or decent engineering workshop can do some stock bends for you and you can fit the lot together, that way you only pay for the stuff you need.

Please don't scrimp on safety.

NEVER USE SQUARE TUBE FOR A ROLLCAGE.

1.
it will never pass an inspection

2.
it is weaker in the wall ( corners are the strength part only, the walls simply hold the corners in place )

3.
Bent SHS requires the tube to become deformed both on the inner and outer radius.

4.
Welded main hoops are a big NO NO !

5.
The corners on a SHS tube will cause much more physical damage to a human body than a round pipe will do.

6.
Rollcage padding is availiable ONLY for round pipe.



Do your self a favor and HIRE a bender for the w/end ...........

and as posted in one of the posts above....... there is NO form of motor sport wich allows SHS for rollcages FULLSTOP.


Kingy

my broyher in law hired a bender to make some sliders last week, it only cost $18 to hire it for a whole day from national hire

Damn.......thats what you get for listening to the local steel supplier! He reckoned box was stronger cuz there is always 2 flat sides at right angle to the force. Only problem with hireing is I live in the bush and Its about 70 mkms to Warwick(if they hire them there) hence trying with box section. Thanx for all the responces....shoulda just asked you guys first!

If you want to buy a bender try. http://stores.ebay.com.au/SUPATOOLSONLINE
He sends alot of stuff through Aussie post.

can't believe steel supplier would think RHS was stronger than tube,

you learn tube is stronger first thing in any tech degree/trade

Benders arent really all that dear to buy either !!

I've seen em advertised for under $200 at places like Army disposals, Supercheap, and the trading post had some a wile back that although were 2nd hand were only $100 from memory !

Buy ya self one ....build ya rollcage , sliders, front bar etc etc then onsell it.

I've had mine for around 15 years now and I have dies to do square and round pipe from 1/2 inch up to 2n1/2 inch round & square.
I've made heaps of bullbars, side steps, sliders, rear1/4 bars & rollbars with it using round pipe.
Also done roof racks, verandas ( curved roof style), frames to hold car fridges, spare wheel carriers, stock crates, horse floats...the list is endless and all from square tube....

Its like a welder, once ya have one ya wonder how the fruit ya ever survived without one.


Kingy