Tubes for a scratch build
Discussion
I am currently designing a scratch built kit car. Obviously I would like this to have a strong and light chassis however at them moment I am having problems finding standards for steel tubing for the space frame chassis.
So far all I have been able to find is mild/low alloy structural steel from Corus which is going to be heavy and not particularly strong or bike tubing which is strong and light but is going to produce a fabulously expensive bird cage type frame. I am open to being convinced that I should use an aluminium space frame.
What sort of tube do I require and where would I be able to source it?
So far all I have been able to find is mild/low alloy structural steel from Corus which is going to be heavy and not particularly strong or bike tubing which is strong and light but is going to produce a fabulously expensive bird cage type frame. I am open to being convinced that I should use an aluminium space frame.
What sort of tube do I require and where would I be able to source it?
will depend on the car you are building and thus the design....
mine being a very large high powered midi, I used 1.5mm ERW tube for some of it 20x40mm and 20x20mm box on the lower frame. The upper is mostly round 1.5-2mm T45 CDS with the smaller diameter infill triangulation from ERW round 1.5mm 20mm or 30mm approx tube.
I also used some 1.5mm folded box sections and realistically using T45 CDS is overkill in anything other than the roll cage on mine.
The Indy (7 type) I have seems to be mostly 1.5mm ERW 20x20mm square tube
Material will also depend on how you intend to weld it as you can't really use T45 if your going to mig it.
mine being a very large high powered midi, I used 1.5mm ERW tube for some of it 20x40mm and 20x20mm box on the lower frame. The upper is mostly round 1.5-2mm T45 CDS with the smaller diameter infill triangulation from ERW round 1.5mm 20mm or 30mm approx tube.
I also used some 1.5mm folded box sections and realistically using T45 CDS is overkill in anything other than the roll cage on mine.
The Indy (7 type) I have seems to be mostly 1.5mm ERW 20x20mm square tube
Material will also depend on how you intend to weld it as you can't really use T45 if your going to mig it.
andygtt said:
will depend on the car you are building and thus the design....
mine being a very large high powered midi, I used 1.5mm ERW tube for some of it 20x40mm and 20x20mm box on the lower frame. The upper is mostly round 1.5-2mm T45 CDS with the smaller diameter infill triangulation from ERW round 1.5mm 20mm or 30mm approx tube.
I also used some 1.5mm folded box sections and realistically using T45 CDS is overkill in anything other than the roll cage on mine.
The Indy (7 type) I have seems to be mostly 1.5mm ERW 20x20mm square tube
Material will also depend on how you intend to weld it as you can't really use T45 if your going to mig it.
mine being a very large high powered midi, I used 1.5mm ERW tube for some of it 20x40mm and 20x20mm box on the lower frame. The upper is mostly round 1.5-2mm T45 CDS with the smaller diameter infill triangulation from ERW round 1.5mm 20mm or 30mm approx tube.
I also used some 1.5mm folded box sections and realistically using T45 CDS is overkill in anything other than the roll cage on mine.
The Indy (7 type) I have seems to be mostly 1.5mm ERW 20x20mm square tube
Material will also depend on how you intend to weld it as you can't really use T45 if your going to mig it.
What grade of steel do you use?
If you are just looking for sizes of section then have a look on www.parkersteel.co.uk You will find common sizes and sections.
As to what you actually use depends on the depth of your pockets! CDS is nice to work with but will cost you about £200-£300 for the steel - speak to Elmdon Metals they are really helpful with grades and everthing. If you want even better than that, use T45. The UTS is about twice that of mild steel but you will pay for it. And because the youngs modulus is the same as mild steel it really is only worth using in the areas that might see high impact (i.e. roll hoop).
I'd steer clear of an aluminium frame. It can be difficult stopping a steel frame from twisting let alone an ally one. You should be able to design a steel chassis that weighs no more than 70kg without any probs. In ally the exact same chassis would be about 25Kg but you will have to beef it up so might end up being 35/40kgs (plus I don't think the MSA or SVA would like an ally roll hoop).
So, for a 30kg weight saving, an ally frame is a lot of expense and hassel.
Needless to say, I'm using ERW.
Cheers
As to what you actually use depends on the depth of your pockets! CDS is nice to work with but will cost you about £200-£300 for the steel - speak to Elmdon Metals they are really helpful with grades and everthing. If you want even better than that, use T45. The UTS is about twice that of mild steel but you will pay for it. And because the youngs modulus is the same as mild steel it really is only worth using in the areas that might see high impact (i.e. roll hoop).
I'd steer clear of an aluminium frame. It can be difficult stopping a steel frame from twisting let alone an ally one. You should be able to design a steel chassis that weighs no more than 70kg without any probs. In ally the exact same chassis would be about 25Kg but you will have to beef it up so might end up being 35/40kgs (plus I don't think the MSA or SVA would like an ally roll hoop).
So, for a 30kg weight saving, an ally frame is a lot of expense and hassel.
Needless to say, I'm using ERW.
Cheers
I used T45 CDS for most of mine with some ERW thrown in for the triangulation, but as said above its not really neccessary unless you are using it to reduce weight by using thinner wall tube.... I used it because I had it for another abandoned project.
T45 is many times the cost of std CDS which is also much more expensive than ERW.
Mostly, IMO well planned mild steel ERW tube is adequate unless you really want to get technical with a complex design (and thus beyond my knowledge).
T45 is many times the cost of std CDS which is also much more expensive than ERW.
Mostly, IMO well planned mild steel ERW tube is adequate unless you really want to get technical with a complex design (and thus beyond my knowledge).
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