Roll Cage Build

[scott180gtb]

Hello

This is my first post in this section. I'm about to to start building a cheapish track weapon. I have been thinking about roll cages as safety first and all that. Has anyone built there own cage? How hard is it to do? I can weld and have work colleges who are coded. I realise that the bends are the tricky bit and there is nothing better than experience when it comes to building a cage. Can you get plans/measurements for building a cage? I'm not interested in racing just something safe for track days.

I have seen this on eBay for pipe bending.

http://cgi.ebay.co.uk/12-tonne-pipe-ben ... 19c23f4008

There are plenty of cars on track day's that don’t have cages. Has anyone had a go?

Thanks

Scott

[MrBenn]

I'm sure some people have built there own, but I think most people just buy a kit of pre-bent tubes and weld them together. Custom Cages, Rollcentre, Sparco all supply cages in kit form, some better than others. IIRC the rollcentre one is about £450.
Alex

[scott180gtb]

I did a bit of research last night and realize just how ill informed my first post is. It seams that about £500 will see you with a decent cage or £750 for Custom Cages weld in one made from CDS. Just out of interest were can you get CDS from. I have had a look at steel suppliers and when you take into consideration steel cost, fabricating time and ultimately a cage certificate there is no sense in making one yourself. Going to start saving. Does anyone need a kidney!

[martinpallot]

I built my own cage:



Those pipe benders are no good for roll cages. You need a mandrel bender to keep the profile of the tube. Your cheapest option is to get a main hoop and front legs from custom cages and some 1.5 metre lengths of tube from them aswell. Then buy a tube nothcher and profile the bars yourself.

CDS isnt cheap. I get mine for making suspension components from a place called ringwood precision engineering. Typical cost for roll cage tubing would be a round 12 quid a metre. I used 27 metres of tubing on my cage

[scott180gtb]

Can you suggest were I buy a mandrel bender? From what i have seen on the net they are not cheap! The cost of the cds plus a mandrel bender surely adds up close to custom cages weld in cage.

Thanks

Scott

[martinpallot]

Definately cheaper to buy a kit from custom cages.

[UweM3]

Definately cheaper to buy a kit from custom cages.

And having a mandrel bender doesn't mean you just bend the tubes you need for ONE cage. Till you worked out how the thing works and get the tubes in the end you need you have filled half a skip up with trial bends.

[DanThe]

Or you could go light weight -

http://cgi.ebay.co.uk/ROLLCAGE-TUBING-3 ... 480wt_1141

[billgatese30]

Or you could go light weight -

http://cgi.ebay.co.uk/ROLLCAGE-TUBING-3 ... 480wt_1141

That's scary, he has obviously never seen the blue book recommendations/requirements.

[martinpallot]

Or you could go light weight -

http://cgi.ebay.co.uk/ROLLCAGE-TUBING-3 ... 480wt_1141

That's scary, he has obviously never seen the blue book recommendations/requirements.

Nothing wrong with that, T45 is much stronger than CDS so you're allowed to go thinner on the tubing.

Buy a T45 cage from custom cages and check out the rear stays, diagonals etc, some are thinner than 1.6mm.


Also, what a lot of people dont realise is that its only the main hoop, front legs and door bars that need to made from seamless tube of a certain diameter and thickness. The rest can be made from exhaust tubing if you want. As usual the blue book is so vague and badly written that there are many misconceptions like this.

[spic]

I built my own rear cage but from a kit from the roll centre, makes life a little more easy to have some one else bend the hoop and cut the lengths though, i found just shaping the ends so they sit in nice for the weld is an art on its own, you might find the roll cage suppliers listed above may sell you CDS tube at a half decent price or just google a supplier in you area.

[UweM3]

Or you could go light weight -

http://cgi.ebay.co.uk/ROLLCAGE-TUBING-3 ... 480wt_1141

That's scary, he has obviously never seen the blue book recommendations/requirements.

Nothing wrong with that, T45 is much stronger than CDS so you're allowed to go thinner on the tubing.

Buy a T45 cage from custom cages and check out the rear stays, diagonals etc, some are thinner than 1.6mm.


Also, what a lot of people dont realise is that its only the main hoop, front legs and door bars that need to made from seamless tube of a certain diameter and thickness. The rest can be made from exhaust tubing if you want. As usual the blue book is so vague and badly written that there are many misconceptions like this.

only because you can doesn't mean you have to. I would never skimp on safety.
For most "homebuilders" T45 is too difficult to hnadle IMHO
and as already posted the roll cage people will sell you the same CDS they bend the cage from for decent money.

for prifiling the ends you want a tube nothcer. But be prepared to have a STRONG drill to run it.

[Mikey_Boy]

Hmmm - seems like a lot of messing around to me when a weld in custom cages multipoint kit gives enough exercise for a good welder, strong shell and enough problems to keep the most Chinese puzzle enthusiasts occupied for weeks!!

See below for details:

http://www.e30zone.net/modules.php?name ... c&t=178370

Cheers,
Mike

[GeoffBob]

only because you can doesn't mean you have to. I would never skimp on safety.
For most "homebuilders" T45 is too difficult to handle IMHO
and as already posted the roll cage people will sell you the same CDS they bend the cage from for decent money.

In full agreement Uwe. T45 is a fantastic material, but a chain is only as strong as its weakest link. If you don't know how to weld T45 properly you risk having weak points in the cage.

[billgatese30]

T45 is slightly stronger than CDS, but 1.6mm is still thin. If it was 4130 then 1.6 is an acceptable thickness, but requires even more prep than T45 to weld (must be TIG'd) and is even more expensive.

As per Geoff and Uwe, I wouldn't be adding any weak links into my cage. Seeing as I have an ability to TIG then anything I would build would preferably be out of 4130 (cost dependant of course).

[DanThe]

Why is it difficult to weld?

[UweM3]

Why is it difficult to weld?

the thinner the wall, the more difficult is is to weld. You should TIG weld it but you can weld it MIG with the correct filler rod.

How many people have a proper MIG welder in the garage, not even talking about a TIG welder?

[DanThe]

You mean its easy to burn away, yes I agree with that but if you can weld an exhaust 'properly' you wont have a problem with 1.6mm tube thats been cut right

[GeoffBob]

T45 can be MIG or TIG welded with with ER70S6 wire. ER70S6 is a steel wire with higher Manganese and Silicon content than standard mild steel wire (see here). While T45 can be welded with a standard mild steel or even a stainless steel wire, this will result in weaker welds. T45 is, specifically, a high carbon steel alloyed with Manganese with a yield strength of around 600MPa for BS4T45 tube (iirc), which is stronger than that of Cromoly 4130 with a yield strength of only ~500MPa. There is no doubt in my mind that T45 is a better material than 4130, but the benefit of either material is in the weight saving over conventional high carbon CDS, which would have to be comparably thicker to achieve an equal strength tube. More important than any of the above is that the tube you choose is seamless, since it is not only the material properties that determine the strength of the tube, but also its form!

BTW, 1.6mm tube is not difficult to weld, it's simply a matter of setting the current correctly and knowing what you are doing. TIG welding while using a pedal to control the current works well, although it is sometimes difficult to find a position where you can work the pedal while wrapping yourself around the cage to get the TIG torch in the right position .

Personally, I have no special tool for profiling tube ends. I simply draw the intersection of two tubes (as per the required angle of intersection) using CAD, and then I plot the intersection rolled out on a flat bit of paper. I then cut the shape out and wrap the bit of paper around the end of the tube. A lick of paint from a rattle-can sets the shape into the end of the tube, and the bit of paper is removed. I then use a small grinder to cut the shape from the pipe. Not as elegant or simple as having the right tool, but adequate if building a cage is not a regular occurrence.

[DanThe]

Good info on the wire

[HairyScreech]

http://www.ozhpv.org.au/resources/shed/tubemiter.html

this boys, is a god send.