Anyone built there own cage?

[maxfield]

Just wondering if anyone has built there own cage here.

Got a welder and a pipe bender.

Going to pick up some 40mm steel this weekend.

Just wondering if anyone has done this before?

What problems might I come accross.

Jamie.

[Rodderz]

I did.. but the bitch got out!

[Rodderz]

Thought I would get in before anybody else did!

[Jon_Bmw]

I would think the steel rating would be the biggest concern...then harnesses to stop you taking up cage banging.

All the faffing about sounds sad when you might get a cage for £400-500.

[maxfield]

I'm going to be buying a bucket seat and a harness anyway.

I can't afford a cage. As I can get steel at a good price. And I have the tools to do it. Plus it keeps me out of mischeif.

[billgatese30]

You need good CDS (Cold Drawn Seamless) at the very least. And then you need to make sure your pipe bender is up to it and won't kink or flatten the tube, kinks are bad and if you have them you may as well not have bothered as they ruin the strength of the tube, it really needs to be a draw-around type rather than a piston pushing in the centre of the bend radius.

You'd be best investing in a pipe notcher too(not too expensive and fit in a decent floor standing pillar drill and just just a hole saw of the correct diameter) as it saves alot of time and effort when you come to butt joints.

Other than that and you should be ok so long as you pick the correct diameter and thickness tube. MSA blue book is probably best for these.

[maxfield]

My cousin's got his own fabrication place so has everything needed.

[billgatese30]

Then just make sure its seamless tube (CDS) and that the tube doesn't flatten out too much and there's no kinks and you shouldn't loose too much strength in the tube.

The other thing to make sure you do (which is like teaching your granny how to suck eggs but I have seen it done too many times) is to make sure that ALL your welds go ALL the way around the joint, not just the bits that are visable. But I would assume you'd be doing that already as your not exactly a plonker. Again, not wanting to sound too preachy but I'm still amazed at how many cages are made like this, its quite shocking really.

[Brian28]

Getting the bends and angles right is tricky, everything else is easy. Main hoop is difficult to get the two main bends done in a nice curve without kinks or flattening. Long bits from hoop along the roof line and down to the floor are difficult because there are a couple of bends along the way, get these wrong and you have huge blind spots at the sides of the screen because of the cage. The bend at dash height to the floor makes a better fitting cage as a compound bend. The rest of it is just cutting and notching straight bits, doddle. Having said that given the price of decent CDS and how easy it is to fk up a couple of lengths, and the time the whole thing takes to do, I wouldn't dream of doing another one. Couple of s/h SD cages advertised at the moment, aternoon with one of those and job done.

[LeonNewton]

i did. with the help of a full workshop and a teem of 3 men with over a hundread years expereance in enganeering and fabrication. you must has CDS as bill has stipulated. make shore your welds are good as well. a lode of snots from an under powered or badley set up welding setup wont do.

haw ever if you or your pall are good fabricators and look at cage design i canot see a problem. if you can get hold of a MSA blue book this will help with making it to FIA criterea.

[maxfield]

Thanks for the advice people.

Looking forward to doing it, it's a bit different from normal mechanics.

[alan1272]

blue book is available online on the msa website should you need to build the cage to a certain spec
http://www.msauk.org/site/cms/contentvi ... rticle=646

[LeonNewton]

That's a good link for the phone. Now I am never withought the bible. Good little cristion.

[UweM3]

Maxfield, do yourself a huge favour and BUY the bendy bits of the cage off the shelf. It's not too expensive and you can buy the straight tube there as well in CDS at a good price. Unless you buy a lot of CDS in one hit, price will be not good.

http://www.customcages.co.uk/roll-cages ... -rollcages

[mattrs]

blue book is available online on the msa website should you need to build the cage to a certain spec
http://www.msauk.org/site/cms/contentvi ... rticle=646

Very handy link! Cheers

[bulletproofbob]

i know CDS is the stuff of choice but as your cage will not be for a race series why not just go for 1.25" nominal bore? it'll bend in a tubella to tight enough bends to do the main hoop (tightest bend needed) and will prevent death in the event of a bump.... its what i made mine of!! £60 all in!!

[Jhonno]

I believe the stuff you have used will split in the event of an accident..

[UweM3]

I believe the stuff you have used will split in the event of an accident..

doesn't really matter if it splits first or just collapses. 1.25"!!!
Wasn't there any smaller stuff available, loool!

[Jhonno]

I believe the stuff you have used will split in the event of an accident..

doesn't really matter if it splits first or just collapses. 1.25"!!!
Wasn't there any smaller stuff available, loool!

[SHAKEELE30]

trust you johnno lol

[RPM]

Maxfield, do yourself a huge favour and BUY the bendy bits of the cage off the shelf. It's not too expensive and you can buy the straight tube there as well in CDS at a good price. Unless you buy a lot of CDS in one hit, price will be not good.

http://www.customcages.co.uk/roll-cages ... -rollcages

Very good advice

[bulletproofbob]

i will not be bothering to quote you all, but the 1.25" nominal bore means its more like 1.5" external which is fine for trackdays the cages i've had in most of my cars have been safety devices and they use similar dimmension tube.... its correctly braced in all the right places, and is welded by a coded welder with tig so there will be no jointing issues... as for the splitting in the event of a crash, it may bo but it will not be a major fail resulting in death... the stuff will not behave like a punctured balloon at first sight of impact!!! i worry at amature welders sticking bits together and thinking they're safe as the tube is cds... i would worry more at the mig'd up seams you have!!!

anyway are you expecting to use the cage again after you fall off the track and into a tree??

anyway, only offered my experience of actually building a cage in a car... obviously the 15 years in the fabrication game are wasted and i wasted my time

anyway, garage is calling, enjoy your CDS fun

[billgatese30]

i will not be bothering to quote you all, but the 1.25" nominal bore means its more like 1.5" external which is fine for trackdays the cages i've had in most of my cars have been safety devices and they use similar dimmension tube.... its correctly braced in all the right places, and is welded by a coded welder with tig so there will be no jointing issues... as for the splitting in the event of a crash, it may bo but it will not be a major fail resulting in death... the stuff will not behave like a punctured balloon at first sight of impact!!! i worry at amature welders sticking bits together and thinking they're safe as the tube is cds... i would worry more at the mig'd up seams you have!!!

anyway are you expecting to use the cage again after you fall off the track and into a tree??

anyway, only offered my experience of actually building a cage in a car... obviously the 15 years in the fabrication game are wasted and i wasted my time

anyway, garage is calling, enjoy your CDS fun

the tubing diameter isn't too bad for certain things (although I would want more for the main structure and use that for door bars etc)


the main thing the blue book recommends (well, it stipulates it, but only for the reason that it is the minimum you should consider) min yield strength of about 300N/mm^2 (or is it 350, i can't remember) and that it should be at least CDS.

This is basically as once the seam splits it will unzip like a pair of cheap jeans and hold virtually zero strength as it offers no rigidity. For your own cages make it out of what ever you please, but I would never recommend anyone to use ERW tubing as you'll never be able to make a strong cage out of it IMO. personally if I had the cash I would go T45 or even 4130 (CrMo).

The other major thing for cage strength is as you say the weld as you need good penetration and complete welds (no gaps) and making sure you get no kinks and flat spots in any of your bends (or that your bends are too tight). the specific recommended regs are in the blue book somewhere but I think your not allowed an oval ratio of less than .8 or .9 I think.

I'm not trying to de-value your skills as a fabricator, but I certainly wouldn't put my name to anything not capable of being able to easily supercede MSA regs for the class of car it was to be fitted into. (I'm also not a fan of bolt in/together cages either for the record).

[bulletproofbob]

i will not be bothering to quote you all, but the 1.25" nominal bore means its more like 1.5" external which is fine for trackdays the cages i've had in most of my cars have been safety devices and they use similar dimmension tube.... its correctly braced in all the right places, and is welded by a coded welder with tig so there will be no jointing issues... as for the splitting in the event of a crash, it may bo but it will not be a major fail resulting in death... the stuff will not behave like a punctured balloon at first sight of impact!!! i worry at amature welders sticking bits together and thinking they're safe as the tube is cds... i would worry more at the mig'd up seams you have!!!

anyway are you expecting to use the cage again after you fall off the track and into a tree??

anyway, only offered my experience of actually building a cage in a car... obviously the 15 years in the fabrication game are wasted and i wasted my time

anyway, garage is calling, enjoy your CDS fun

the tubing diameter isn't too bad for certain things (although I would want more for the main structure and use that for door bars etc)


the main thing the blue book recommends (well, it stipulates it, but only for the reason that it is the minimum you should consider) min yield strength of about 300N/mm^2 (or is it 350, i can't remember) and that it should be at least CDS.

This is basically as once the seam splits it will unzip like a pair of cheap jeans and hold virtually zero strength as it offers no rigidity. For your own cages make it out of what ever you please, but I would never recommend anyone to use ERW tubing as you'll never be able to make a strong cage out of it IMO. personally if I had the cash I would go T45 or even 4130 (CrMo).

The other major thing for cage strength is as you say the weld as you need good penetration and complete welds (no gaps) and making sure you get no kinks and flat spots in any of your bends (or that your bends are too tight). the specific recommended regs are in the blue book somewhere but I think your not allowed an oval ratio of less than .8 or .9 I think.

I'm not trying to de-value your skills as a fabricator, but I certainly wouldn't put my name to anything not capable of being able to easily supercede MSA regs for the class of car it was to be fitted into. (I'm also not a fan of bolt in/together cages either for the record).

thats fair enough, but i'm a trackday man, and i assume as the question was asked its is destined for a non MSA car... the seams have stood a near 90 degree bend in the tubella, but your right they risk splitting in the sudden impact of an "off" but i'm ongoing with tabbing the cage into the shell as much as possible and as such i really doubt the tube will split!!

your tube suggestion is spot on if funds allow, i think the T45 is spot on, the CrMo is defo overkill but if funds are there why not, i work mainly in CrMo and mid Cr with quite a bit of stainless thrown in and it is some seriously good gear, and the wall thickness can be lowered hugely! mind you the skill of the welder then becomes even more important, as does the potential issue of the heat effected zone either side of the weld and the loss of strength if excessive heat is imputted... oh i think this may be over the top for DIYing cages ha ha

[billgatese30]

i will not be bothering to quote you all, but the 1.25" nominal bore means its more like 1.5" external which is fine for trackdays the cages i've had in most of my cars have been safety devices and they use similar dimmension tube.... its correctly braced in all the right places, and is welded by a coded welder with tig so there will be no jointing issues... as for the splitting in the event of a crash, it may bo but it will not be a major fail resulting in death... the stuff will not behave like a punctured balloon at first sight of impact!!! i worry at amature welders sticking bits together and thinking they're safe as the tube is cds... i would worry more at the mig'd up seams you have!!!

anyway are you expecting to use the cage again after you fall off the track and into a tree??

anyway, only offered my experience of actually building a cage in a car... obviously the 15 years in the fabrication game are wasted and i wasted my time

anyway, garage is calling, enjoy your CDS fun

the tubing diameter isn't too bad for certain things (although I would want more for the main structure and use that for door bars etc)


the main thing the blue book recommends (well, it stipulates it, but only for the reason that it is the minimum you should consider) min yield strength of about 300N/mm^2 (or is it 350, i can't remember) and that it should be at least CDS.

This is basically as once the seam splits it will unzip like a pair of cheap jeans and hold virtually zero strength as it offers no rigidity. For your own cages make it out of what ever you please, but I would never recommend anyone to use ERW tubing as you'll never be able to make a strong cage out of it IMO. personally if I had the cash I would go T45 or even 4130 (CrMo).

The other major thing for cage strength is as you say the weld as you need good penetration and complete welds (no gaps) and making sure you get no kinks and flat spots in any of your bends (or that your bends are too tight). the specific recommended regs are in the blue book somewhere but I think your not allowed an oval ratio of less than .8 or .9 I think.

I'm not trying to de-value your skills as a fabricator, but I certainly wouldn't put my name to anything not capable of being able to easily supercede MSA regs for the class of car it was to be fitted into. (I'm also not a fan of bolt in/together cages either for the record).

thats fair enough, but i'm a trackday man, and i assume as the question was asked its is destined for a non MSA car... the seams have stood a near 90 degree bend in the tubella, but your right they risk splitting in the sudden impact of an "off" but i'm ongoing with tabbing the cage into the shell as much as possible and as such i really doubt the tube will split!!

your tube suggestion is spot on if funds allow, i think the T45 is spot on, the CrMo is defo overkill but if funds are there why not, i work mainly in CrMo and mid Cr with quite a bit of stainless thrown in and it is some seriously good gear, and the wall thickness can be lowered hugely! mind you the skill of the welder then becomes even more important, as does the potential issue of the heat effected zone either side of the weld and the loss of strength if excessive heat is imputted... oh i think this may be over the top for DIYing cages ha ha

Yeah, 4130 is way overkill for most trackcars, we are going to have to use it soon to bring a space frame chassis up to spec so it can be tagged to run down to 6 second 1/4 mile times, your best off pre-heating it prior to welding to help control the amount of heat to avoid changing the steel properties too much, just need to get some appropriate filler rods and some lengths of 4130 (and my brother to get his finger out of his arse and actually get the motor built up)

[bulletproofbob]

you'll not be far off using a standard 2.25%Cr filler wire, with the dilution from parent material it'll be pretty much spot on!! yeah the advantage of sticking a bit of insulation over the weld for 5 mins after completing the weld are not appreciated generally either ha ha

[UweM3]

What puzzles me in discussions like this is the seperation of risk. "it's only for trackdays..."
Do you get lighter injuries in trackdays compared to races? I don't think the obstacle on a race track does bother if there is a trackday or race car bouncing off it.
There was no criticism of fabricator skills etc, it was just the choice of material. Why do you think the blue book has these minimum requests? These have derived over years buy looking at crashed cars.

If you decide to fabricate your cage from skinny handrail tube, fair enough. It's your own life and health. Heve you ever tested your cage? What makes you believe that it is strong enough.
I am a skilled fabricator myself, but if you are not directly working in the same field (i.e. making loads of cages and seeing them also crashed afterwards) it can sometimes be a bit misleading to tack a bracket on and think yeah that is doing the job just because somewhere else it was fine.

Safety is nothing to skimp on. You may never need your cage, that would be the best scenario.
But IF you need it you want to be sure it's doing the job. Better a little bit overkill and safe.
How much money are you going to save with ERW tube compared to CDS? 100-200 quid.

So as long you haven't produced plenty of cages which have proven to survive a decent impact
you know noting. And I don't mean this offensive, it's just the reality.

[Brian28]

Although smacking hard into something solid is likely to have the same outcome regardless of how it happens (road track day race), I think the difference in risk is about personal choice. IE on a track day you can choose to drive at 90% to leave a margin for error and create a lower risk environment for yourself. When racing you don't have that choice, as the impact may well be a T bone from somebody else driving at 101%.

[GeoffBob]

To add my few pennies worth to all the above...

T45, 4130 and other specialist structural steels available from Elmdon Metals. T45 is a carbon-manganese steel alloy with a yield strength (the point at which it begins to stretch) of around 620MPa, well in excess of MSA requirements. Most usefully, T45 does not require any pre or post heating before welding. It's a fantastic material to work with.

For the track day enthusiast on a budget, a high-carbon seamless steel pipe (steam-pipe to many people) is ideal (and really not that expensive compared to the cost of a protracted stay in the ICU). Unfortunately, to achieve similar strength, a wall thickness of at least 3mm is recommended on a 42mm OD pipe. This makes for a particularly strong, but heavy, cage. personally I would rather my car gain some weight than I lose my head. Alternatively I would wait and save up for some T45 or 4130 if weight is a big issue.

Standard 300MPa mild steel might work if it weren't for the seam. The actual tensile strength of the chosen material means nothing if the form of the material has limited structural integrity - which is precisely the reason the industry standard specifies seamless tube. Ever seen a cage made from rod, flat bar or square tube? That's because these forms lack structural integrity. 300Mpa mild steel is actually a very strong material, but in the form of a tube with a seam you might as well build the cage from flat bar! The fact that a seamed tube lacks structural integrity is the reason it cannot be used for carrying high pressure steam, and is the reason steam-pipe is a useful alternative for making a roll-cage.

The golden rule to keep in mind - the strengh of any piece of steel is not only defined by the properties of the steel (alloyed with Crome, Molybdenum, Manganese etc) but also the shape and form of the piece.

[Jhonno]

Uwe.. Couldn't have put it any better myself, exactly what I was going to say (apart from the being a skilled fabricator), but not had the time to type..

As GBob says, it's not the material properties of the tubing that is the issue, it's the form in this case that is the problem. What has been created is a glorified strut brace for the whole car..

[UweM3]

Although smacking hard into something solid is likely to have the same outcome regardless of how it happens (road track day race), I think the difference in risk is about personal choice. IE on a track day you can choose to drive at 90% to leave a margin for error and create a lower risk environment for yourself. When racing you don't have that choice, as the impact may well be a T bone from somebody else driving at 101%.

I hear what you are saying. But NOBODY wants to crash, neither racer or trackday enthusiast. These things are called accident because they just happen. You may well only drive 90% (what you should do anyway on a trackday) but Mr.Stupid in his underspecced, brakeless,scrapyard tyred XYZ may not.
Or there is a fluid spillage and you shoot straight without the ability to steer instead round the bend. Motorsport is dangerous, in any form.

[Brian28]

[
but Mr.Noob in his underspecced, brakeless,scrapyard tyred XYZ may not.
.

I've seen that chaps name, he is a member and posts on here. Think that's a bit harsh about his car tho (Sorry Noob)

[UweM3]

[
but Mr.Noob in his underspecced, brakeless,scrapyard tyred XYZ may not.
.

I've seen that chaps name, he is a member and posts on here. Think that's a bit harsh about his car tho (Sorry Noob)

Oh Sorry! Didn't realise this was a users name. Please accept my apologies

have edited my original post

[89pgy]

I am with Uwe ,if you spin at 90% of your driving skill and are across the track at say the bottom of paddock hill on brands and i come through the corner at 90% of my driving skill and hit you side on i would want to know that cage is not going to brake and stab me in the side.
A cage is not something to cut any corners on,fittted and trangulated correctly it will make your car safer and handle better.Fitted incorrectly by somebody who just whats bars the the car because they look cool it is a killer.Sorry had a bit of a rant there.

[Brian28]

But I wouldn't spin at 90% a spin is over 100% . Points taken, I'm not suggesting that anybody cuts costs with safety, but the reality is that there is less risk on track days than racing. That's why insurance costs more, and why you will be kicked out if caught timing laps on a track day.