Sau Roll Cage Thread General Discussions

[Bsa]

This is a general dissuasions thread for roll cages it's a chance to ask traders directly also to learn general things about building cages I'll post what obsicals iv come across in my experiences as others can do also.

Edited April 26, 2012 by Bsa

[BOOZTJUNKEY]

Very good idea I wanna build mine aswell...

So there could be a lot of helpful info

Top work mate

[ISL33P]

Brad......BSA.....anyone???? Anyone have any questions? I reckon this will get some people started.

I might put my 2 cents in to get things underway. From experience, for anyone wanting a roll cage or anything car related, know exactly what you want from the start.

- Street or track or both?

- removable or welded in or a combination of both?

- material type? CDS or Chromoly? Moly is lighter but only a little more expensive. Disregard what anyone says about it being ridiculously more expensive. According to rules books, the

- mig welded or tig welded? (IMO mig isnt an option, but a lot cheaper because it quicker but not as strong)

- additional bars? roof X, side intrusions, windscreen pillars, harness bars, main hoop X, backstay diagonals, harness mounting, gussets?

- what will need to be removed or cut inside the car to suit the roll cage?

- will the cage builder want the car bare/stripped?

There are the majority of the considerations, apart from your budget of course, to give you an idea of what kind of direction you want the car to go in.

Since a basic 4 point, back half, cage is the most popular DIY cage. If anyone likes, I am happy to go through what you need to at least have a cage measured, which you can then have anyone with a tube bender, bend it for you and then head back home to continue the DIY instal.

[Risking]

Cams and 4130 is not an overly easy thing to do though.

There is a couple of ways to go about it.

Build the cage to all the material dimension requirements but use 4130 instead. The cage builder must contact cams before beginning and request a 2nd dossier that needs to be completed. It requires detailed drawings and each bar to be described in detail.

Cams then provide a separate authority number and form. Cage won't be any lighter than a conventional CDS version as 4130 is almost identical weight per cubic inch.

2nd way to submit a dossier to the FIA/CAMS. Attached must be a more comprehensive drawing of the cage, bar descriptions and the

expensive part the FiA recognized engineers reports with FEA simulations. Dynamic load tests, repeat cycle load simulations and specified load tests post initial material deformation.

The homologation papers are then provided to

the cage builder and further inspections are required after construction.

Advantages are we can use material down to 1.6mm in some areas. Obviously being lighter than the CDS.

The age will ultimately be stronger due to more diagonal construction being required and the increased tensile strength of 4130/T6

Disadvantages cost of the engineering and FiA paperwork, the additional bar work required obviously extends the cost even further as more material is needed and the bars required are usually fairly complicated buggers so the labour cost goes up as well.

The final way which I've seen many failures and some success with is T6 cage kits from places like Custom cages in the UK.

They apply for the FIA homologation and provide you with a kit.

The installer must pass a weld test before the papers are given to you though.

Also the FiA regs change constantly and I've had cages come across to aus that have changed hands several times and are no longer up to date. What seems cheap for a T6 cage could end up being useless when you apply for certification. Best to contact Rupert at cams before buying an overseas or local cage to confirm the homogation is current for the specific cage kit your buying.

I'll post up a couple of FiA submitted cages I've done in the last couple of days.

One is for an r34 4130, an s13 and an r32 GTR.

All are being done the 2nd option way which in my opinion is the only beneficial way to do a 4130/T6 cage in aus and never have a problem with compliance.

Andra have a totally different set of 4130 rules which require no form of dossiers, applications etc just post inspections and in my opinion silly ways of allowing cages to Be built with bent rear legs and 0 triangulation etc.

[Risking]

R32 GTR Drafts done for FiA homologation.

We are using a recognised software recommended by the FiA. Its fairly powerful stuff specificly written to design and simulate cages. Ive now bent up a couple of hoops and legs using no templates only the software drawings, touch wood they have been prefectly accurate.

Obviously the software can only be as accurate as the information it is given though.

And a pair from the R34 drafts

If people want to see more drawings and more of the indepth FEA anylise then I have loads more that can be posted up.

[DCIEVE]

If people want to see more drawings and more of the indepth FEA anylise then I have loads more that can be posted up.

Yes please. Program (guessing a beam element limited software), load cases/combinations, assessment criteria etc.

Edited May 13, 2012 by DCIEVE

[ISL33P]

Sounds like you have done the odd cage here and there Brad lol

ANDRA is currently undergoing some major reviews of their cage requirements, so we will see what comes out of that. Having said that, maybe it's just luck but I doubt it, it's current standard seems to do the job on the track when it comes to occupant safety, so it can't be too bad.

Personally I would prefer less bends in the front and not care too much about what is behind me, but basic specs for the front are quite similar for CAMS and ANDRA, but yes the rear half is COMPLETLY different.

[Risking]

Hahaha yeah I've done my fair share of cages.

We're not even 6months into the year and I'm into the 9th large cage so far for 2012. I had a look in my diary today and there is already 8 more penciled in to be called up when time permits.

I'm doing a really large FiA T67 cage in an r32 currently.

I might do a photo diary of it's construction on here.

[ISL33P]

do it do it!!

[Bsa]

Do it polty

[Risking]

This one is being done for an a customer who is on SAU but will own up to the car if they want to.

The car came to me as a complete imaculate rolling shell. Dylan has become extremely handy at getting these things pulled down and made short work of stripping the interior and then all the sound deadening and alot of the body sealer too

This is what a car needs to be stripped down to for a job like this to be done properly.

The shell still needs some preperation before the cage can be done. In the front ive removed the factory dash bar brackets on the A pillar. Reason for this will become apparent latter on. But it needs to be done now.

Also any other brackets and studs are cut or drilled out now before going any further.

The car at this stage is also leveled on stands or my hoist pad depending which part of the workshop its going to. The reason for leveling the chassis is so we dont permanantly fix a tweak into the body if there is something mismatched about the ride heights or spring rates etc etc

On the hoist bed (belly lifter) there is also points to strap the chassis down should it have a tweak that gravity and stands can rectify.

Once the chassis is level I can measure it up and get a hoop drafted.

Base plates are then fabricated and can be tack welded into position. There is heaps of different ways to do these but it all comes down to which way your comfortable with welding the hoop.

In this case ive opted to do a corner reinforcement base. it will provide a gusset in the corner of the seat pan and sill pannel. It will also provide me with a good base for something a little tricky latter on in the cage fabrication.

The legs also got done yesterday afternoon but more on those after todays work.

Hoop bent up and installed it now looks like this

[UWISSH!]

How much are you guys buying the lengths of pipe for to do all the legs and other braces?

Not chromoly pipe just CDS pipe, coz I want to have a go at building my own n just want to see what pipe costs.

[Risking]

What I pay and what it gets sold for a two very different things.

I buy enough material at a time to do 30 cages.

I know race tech and performance metals are currently selling CDW for $9-14/meter.

CDS for between $14-22/meter

4130 goes for $19-32/meter

[UWISSH!]

Ok coz through my work I got quoted $220 for a 5.8 m length of. CDW tube 38.1mm x 2.6mm wall.

Thought it was abit much

Thats 355 mpa yield strength

[Risking]

That's an odd length dimension.

Most lengths I see are either 6.8 or 7.2.

Email me a list of what you need and happy to send you a quote when I get a chance.

There are also various types of CDW out there. Some I've found are grainy as hell and horrible to work with. One supplier has an abundance of that stuff at the moment and is selling it off very cheap. The good stuff is alot nicer to weld, has a good surface finish and isn't as cheap.

[UWISSH!]

Ok no worries, I'll talk to the guy who I'm going to get to bend up my hoop n see what price he will do for me, if it's not good I'll send u a list of what I need ok.

Thanks heaps for your help

[ISL33P]

looking at 20-30 metres for a decent 6 point cage, so that makes it around $600 in material @ $20 p/metre

[Risking]

Here is some of yesterdays work.

There is alot of time put into these types of cages and having to run the bussiness, adds considerable ammounts of time to the job

First up after the legs and hoop are done is the front windscreen support bar.

This has two bends and sit about 10mm rearward of the screen bulkhead at roof level

Following that are the two bars that form the roof X. They are again bent uptowards the roof and are knotched into the intersection the front leg and screen support bar form. The meet the main hoop at roof level at a pre planned position where the rear legs will also meet the hoop.

It now looks like this tacked together

Next some of the most important bars in a 4130 cage. The leg and screen additional support bars.

The front screen bars are straight and meet the screen support bar at a location determined by the simulations.

The hoop to leg supports done in this cage are bent outwards towards the B pillar to allow room for the seat to fit comfortably. Ive also done them to follow the line of the B pillar so from the outside of the car they are not as obvious.

All sitting in position with those bars this is it.

The cage is now dropped from its base feet and the top sections are fully welded.

Photos of how thats done latter.

[ISL33P]

some nice moly welding tips here.....don't forget, practice makes perfect!!!

[r31slpr]

I've been thinking about getting a bolt in half cage lately and noticed that lots of people are hating on bolt ins, saying that they are not really that great in a rollover and are more for rigidity.

I haven't spoken to any actual cage builders about this yet.

But from what i can see on here, 'Risking' and a few others do this for a living. So i thought i'd post up here and see what peoples opinions on bolt ins are.