Iv decided with the help from a friend that we are gonna do it ourselves. All I need to know is how much bar to order.
Obviously il order slightly more than what's needed just incase but I'm not sure how much to order. This is the base we are gonna go for.
Could you not measure up inside the car? I'm assuming you have a proper mandrel bender to use aswell?
Just fyi when pricing up my weld in cage a friend was designing it worked out around 4-500in cds tubing to allow for errors and excess cuts etc that was more like a 14 point full out cage. But I'd imagine you'd be near the 400 mark
is it for Competition
11.5 meters seems a bit excessive.
Get one from apex (hint: they are the ones you want to copy), it will be safer, cheaper, done faster and prettier. They sell for 379£ if memory serves. You cant beat that.
No I'm set on doing this myself now. And doing this myself will cost a fraction. The picture iv put up is just to show the rout for a start the plan is quite elaborate once we have the base. Thanks for all your comments helpful or not
Last edited by Samburton4; 18-12-2012 at 15:56.
most events require the cage to meet MSA FIA Certification, home made would cost a lot to get certification
No shit sherlock ! That was quite obvious.Originally Posted by Samburton4
You could not be more wrong. You dont even know how much tubing you need, nor the price of any inspection; how can you say it is going to cost less ? You really think a one off prototype from an amateur cost less to build than batches from outside your country ? Just the tubing will set you way off apex price. And then there is coating, bolts,brackets, various hardware, inspection, bends, welder parts and time. This is considering there is no waste / junk / error and your prototype is perfect on the first run.
Even if the time is free, it will still cost you more. I cant believe you do not see that.
You clearly have no idea of what you are talking about. Lets just hope for your wallet that you see the hard truth before buying anything. Your money, not mine.
I will apologise that after going and measuring the car tonight we are looking at 19metres of tube. But don't come on here and say shit when you have no idea of what someone is capable of. Usually I wouldn't bother responding to this but for your information I'm a cnc engineer so all the plates tabs bolts will not cost a penny and for my friend that's helping. He works for Radical building sports cars from scratch so just don't bother if you don't have anything helpful to say
I still bet you cant make a better cage or just an even cage than the one you want to copy for less. Of course, if you plan to steal materials from your workplace, it will cost less. Is that what you call "you have no idea of what someone is capable of" ?
Yeah well, just go and steal one from apex while you are at it. It will even be cheaper sherlock !
^^^^^What a complete dick you are.
The guys a proper engineer and so is his mate that's helping, building a cage is not rocket science, as for as "stealing from his workplace" you don't know he's doing that, he might be getting off cuts for free or might even say to his boss "can I have this?"
All he wanted to know is how much bar he would need and you've jumped on his thread and basically called him a thief and told him he doesn't know what he's doing.
Whilst our Gallic friend is making his point in a fairly confrontation way (and not for the first time), it is a valid debating point.
A certified cage is the only cage that really has any validity. Anything else is just ornamental so if you want to protect yourself in the event of an off-track excursion, you really need a cage that you are very confident is going to protect you rather than something that might or might not.
Otherwise, you are making yourself into a crash test dummy.
From a cost point of view, the materials are not cheap unless you buy in bulk or can get a massive discount through work. Perhaps you can also get mate's rates on the inspection.
If you haven't considered these things, it is worth doing so before getting started.
For most people, maybe or maybe not including yourself, the path of least cost, greatest safety and least resistance would be to buy the Apex cage.
No mention of constipated, pooping fictional detectives required.
Surely a cage is a cage? As long as you can weld to a good standard (i.e MOT or better) then how is a non certified cage going to be any weaker than a certified one? End of the day its just scaffold bars weleded together, its not rocket science
Obviously if he said he was going to make it out of 1mm thick tube and gaffer tape it together ge would have a problem
The guy can do as he likes. I'm not going to be getting in his carSurely a cage is a cage? As long as you can weld to a good standard (i.e MOT or better) then how is a non certified cage going to be any weaker than a certified one? End of the day its just scaffold bars weleded together, its not rocket science
Obviously if he said he was going to make it out of 1mm thick tube and gaffer tape it together ge would have a problem
Tell me though, Mark, what is the weakest point on a 6-point cage and how much force will that weak point take before folding ? What force is likely to be applied to the cage in a side-impact with armco at 70 mph ?
I dont know, i am not a materials engineers
But if you copy the design of a proven cage how is it going to be significantly worse? and its got to be better than no cage
i think cages are dumb on a road car anyway as they reduce the head room inside the car and if you have an accident on the road when you are obviously not wearing a helmet you will probably do yourself more damage smacking your head against it
It's not exactly rocket science (and having done rocket science, that's not exactly brain surgery).I dont know, i am not a materials engineers
But if you copy the design of a proven cage how is it going to be significantly worse? and its got to be better than no cage
i think cages are dumb on a road car anyway as they reduce the head room inside the car and if you have an accident on the road when you are obviously not wearing a helmet you will probably do yourself more damage smacking your head against it
Calculations on structures of tubes are a piece of piss. Do rollcage fabricators actually design cages properly or just follow rules of thumb? Its easy to build in some real weak spots, that only come out when you analyse it. Anyone can do the analysis with a basic FE package.
I was going to post on this last night - I actually agree with croustibat most of the way - not the way he delivers his message mind
if there's as much competence involved that we're being told, surely the first part of the job is being able to measure up your requirements to your specifications rather than relying on the internet to tell you?
I'm all for being able to do stuff yourself, even if the cost is higher, given that you're learning at the same time but for something like a cage? it's going to be around £250 (£13ish a metre, assuming a very generous trade price) for the steel alone, plus grinding discs, gas, welding wire etc etc
that's not including the time and learning curve.
the question would be - do you plan on doing it a second time?
white '94 s13 200sx scrapped - mapped to 1.45bar. OS giken box, garrett GT2876R, 950cc injectors, ORC twin plate, nistune. 349bhp/325lbft @ 1.3bar CA18DET
white '96 s13 180sx - type g with more kouki bits- RB25DET, GTR steel twin turbo conversion, RB26 crank & rods. 2.6L VVT twin turbo, SR20 OSG box, OSG STR twin plate clutch, Z32 ECU w/ nistune.
current status: 180 a bit broken but to be repaired.
There is no 'certification' of off the shelf roll cages, you can't buy a pre-certified cage they are just made by the manufacturers to fit the correct regulations regarding material, dimensions, welding spec etc...
The 'certification' occurs when the vehicle is presented for scrutineering where they will check the cage against the appropriate regulations so there is no issue making your own cage provided it complies with all the rules and regulations (MSA blue/red book in the UK),
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Prodrive used to spend huge amounts of money having sample cages sent to Europe to undergo special testing in what as far as I know is a one off piece of equipment, but Im sure they just do that for a laugh, weld some tube together in a car and its near enough the same thing, lol. But in all fairness a proper home made a cage is fine, if you are competing a local MSA bod will certify your cage, no different to having a off the shelf cage been ticked off for correct fitting, sometimes they are far to slack sometimes to strict, I bought a cage from a championship winning car and the welding on the door bars and harness bar was a total joke, should have never been out racing but passed fine.
Cages in road cars can be dangerous, a young lad died in a relatively small accident last year because his head smashed on his Chinese made show cage, pad them up right with proper MSA approved stuff that wont give you horrible 1st degree burns if your car goes up in flames and you'll be fine, thou id still be tempted to have a lid on even on the road.
As far as I'm aware this is correct.
Dunc.
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