TheSamba.com :: View topic - Building roll cage, tube thickness and diameter?

Tue Oct 19, 2004 3:37 pm

I bought a 12 ton tubing bender new from harbor freight and decided to make my own roll cage for my full legnth manx style. I am going to make it 12 to 14 point and anchor it to the pan and not the body. it is going to have hoops around the windscreen and behiend the front seats, along with tumbing arround the foot well.

My question is what diamater and thickness of steel do i need to make this for safty?

Tue Oct 19, 2004 3:41 pm

1.50" x .09" should be a good size for a car that light and with the size of cage you plan on building

also, what you picked up from harbor freight, was it a tubing bender, or a pipe bender? pipe benders do not bend tubing well at all. tubing will fold after about 10 degrees of bend

Tue Oct 19, 2004 3:53 pm

I saw your buggy it looks good. It is a manx style full legnth and i want to build a cage that is stron and keeps the chassis ridgid. I would like tubes run between the seats and the fiberglass on the inside of the tub but the seats are less that 1 inch away so i dont know if this is possible.

As for the bender 12 TON HYDRAULIC HORIZONTAL/VERTICAL PIPE BENDER

Make precise bends in aluminum and rigid steel pipe. This unit bends 6 different pipe sizes from 1/2'' to 2'' diameter and has 2 rollers that can be adjusted from 8-1/2'' to 20-1/2'' to accommodate the distance needed.
Roller adjustments: 8-1/2'', 11'', 14'', 16-1/2'', 19-1/4'', and 20-1/2''
Precision cast dies
Die sizes: 1/2'',3/4'',1'',1-1/4'', 1-1/2'', and 2''
Jack: 9-1/2'' stroke
Bends up to 90°
26'' steel handle
Overall dimensions: 24''L x 4-1/2'' W x 21-1/2''H
Shipping weight: 92-1/2 lbs.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=38024[/url]

Tue Oct 19, 2004 4:00 pm

yeah, return that. it wont work for what you are trying to do.

obviously you have some fab skills or you wouldnt be attempting something of this magnitude. one of these days i'll build myself something like this. i suggest doing the same yourself if you dont want to spend the cash for a real tubing bender

http://www.blindchickenracing.com/Tools/Tube%20Bender/Tubingbender.htm

Tue Oct 19, 2004 4:05 pm

I actually wnet to the blind chicken shop in Oregon and talked to the guy. he wanted $600-800 to build me a cage and i figure i could make one myself for less and have the bender. Why will this one not work?

I am not bending more than 90 deg.

Tue Oct 19, 2004 4:07 pm

i actually had purchased the same bender. like i said earlier, once you get past about 10 degrees, the tubing begins to fold instead of bend. real benders actually control the inside diameter and pull the tubing into the bend instead of pushing it.

Tue Oct 19, 2004 5:31 pm

shoot hamburger, wtf dont you know ?? :lol:
i like your new flapjack rabbit.

Tue Oct 19, 2004 8:39 pm

Hamburgerbrad,

Ok if i return the bender i bought, where do i find one that is sufficient? or will do the job.

Tue Oct 19, 2004 9:30 pm

Michael16 wrote: Hamburgerbrad,

Ok if i return the bender i bought, where do i find one that is sufficient? or will do the job.

well, you can build a copy of the BCR bender, check out a tool supply house, or look on ebay for something that actually pulls then bend instead of pushes the bend

Tue Oct 19, 2004 9:45 pm

The bad news about the benders that actually work on tubing is they cost about 10 times more than a pipe bender. Figure on spending at least $500 plus for anything worth a shat. If you can't get a cash return at harbor freight, trade the bender in on a tubing notcher. These tools are fairly cheap and if you have a drill press they are very handy too. They provide excellent fish mouth joints on tubing.

My suggestion for your cage would be to do your own, but instead of performing the bending yourself take it to a muffler shop. Their benders run in the $5,000 to $20,000 dollar range and usually provide excellent bends. To establish the radius and length you will need build a simple mock up cage. Buy yourself a 3/4 inch conduit bender. The kind you attach a pipe to and press on with your foot. They are fairly inexpensive and available at most hardware stores. Also, buy a few sticks of Electrical conduit and basically build yourself a cage without welding it together. The conduit is dirt cheap and pretty easy to work with. Once you have a game plan take it to a muffler shop and have them transfer your design onto 1 1/2 TUBING. Do not use pipe. I would suggest ..95 wall tubing. My guess is most shops will perform the needed bends for less than $5 per bend.

Hope this helps.

SHMO

Ps: whenever building a cage for recreational use keep in mind that you will have to co-exist with it. Allow plenty of elbowroom, ankleroom and legroom. Also, Make sure you can operate everything without interference. There is nothing worse than welding a cage in and finding out you can’t roll the windows down or reach the turn signal switch. Banging your ankle every time you enter and exit also gets very old very fast

Tue Oct 19, 2004 10:07 pm

i have kind of a related question here; does it make much sence to start with a class11 cage, weld it yourself, and build off of that to tie into the front and rear bumpers? i was thinking that would save me a lot of trouble and give a good base to work from.

Tue Oct 19, 2004 11:47 pm

SHMO, cant fortget headroom. possibly the most important. some of the muffler shops i went to were around $5-$10 per bend, but of the three i went to, none of them had a mandrel bender. all of their machines would cause the inside section of the tubing to crush in a little bit instead of having a smooth radius for the entire length of the bend. look at their machine and a sample of their work before you commit your material to their bender.

and ft irwin, those cages are for bajas. i believe michael mentioned this was going in a manx. probably not the best start in his case

Wed Oct 20, 2004 12:28 am

yeah, good point.

Wed Oct 20, 2004 8:53 am

I will look at the BCR bender and maybe talk to Mark there and see if he can help me find the parts to make one then. Just making the bender will be a project in instled before the actual project.

Brad is there an online tool place for the parts?

Michael

Wed Oct 20, 2004 9:22 am

i think they mentioned in their bender construction page where they got their parts. if thats what parts you were asking about?

Wed Oct 20, 2004 6:14 pm

it might not be a bad idea just to let blind chicken racing do your cage.

Thu Oct 21, 2004 10:04 pm

the biggest difference (imo) why that bender wont work is not the push or pull of the media being bent, its the dies are different. tubing is measured o.d., and pipe is i.d. thats why those benders suck for tubing. m-tech supply in mesa,az has benders startin at around 350. but that doesnt include dies. just my $.02. great investment, that will pay for itself in side money and then some.

http://www.mtechsupply.com/

good luck whichever route you choose.

Thu Oct 21, 2004 10:52 pm

[email protected] wrote: the biggest difference (imo) why that bender wont work is not the push or pull of the media being bent, its the dies are different. tubing is measured o.d., and pipe is i.d. thats why those benders suck for tubing.
this is also true. but the controlled pull around the die and being held back against the cradle is what gives you the smooth bend

compared to http://www.pro-tools.com/200.htm the company you posted for the affordable bender charges about $50 more on average for the dies, and that bender you were talking about is manual and the hydraulic conversion for it costs nearly $400. just a thought.

Fri Oct 22, 2004 9:59 am

I returned the harbor freight bender yesterday. i looked arround the inter net and found the Model 3 bender made by JD squared out of FL. the bender is 295+240 for the die and 15 for the deg. indicator.

I think this is the route i am going to go. Anyone have one of these benders. 1.5" tube and .095" thickness good for a 12 point cage for a manx?

Fri Oct 22, 2004 11:53 am

i'm interested to see how this bender will work out for you. it may be the route i choose as well. keep us informed.

and as answered earlier, . 094" wall should be plenty strong for your cage