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Questions about metal types and whatnot
MrTom - 15/1/08 at 06:30 AM

So I'm about to start my chassis build from scratch. I'm trying to figure out a few things, as for the length of metal I need overall I've been taking notes as to what other people bought, I figure I'd rather have a lot left over than not enough the first go around.

But for the majority of the chassis, what is better? Hot roll or cold roll? (A36 vs A513) Is there a reason it's square tube or is that just for simplicity's sake?

Should I have my engine/drivetrain/suspension worked out before i start the build or can I get the basic chassis hammered out and worry about the little things later?

Will MIG be good enough or should I TIG everything together?

And most importantly, how tall of a person does the 'book chassis' allow? I'm pretty tall and if I need to make it longer to fit I'd rather find out before I start cutting and welding.

[Edited on 15/1/08 by MrTom]


NigeEss - 15/1/08 at 08:43 AM

RHS 1.6mm wall is accepted standard and simplest. Round fine but the fishmouths
needed are a ball ache.

For book/McSorley standard chassis you will need :

1200" (5 1/2 lengths) 1" RHS
295" (1 1/2 lengths) 3/4" RHS
295" 3/4" round
32 sq" 1/8 flat plate.

All assuming you get all cuts spot on first time........yeah, right

Standard chassis will easily accomodate over six footers but if you are on the lardy side
then +2" in the width is worth it.

Mig is what most people use successfully and the engine details can easily be sorted after the basic chassis is built.

Do be aware of the errors in the "book" regarding FU position and wishbone
design. Do a search here or check Flakmonkeys excellent sebsite build log.

Good luck.


AdamR - 15/1/08 at 09:26 AM

I added 2" on extra length to my chassis over concerns about space, but it was totally unnecessary as there's loads of room.

You do need to give some serious consideration to engine & drive train before you get too far into the chassis. Engine choice is normally the biggest factor in whether you need extra width (+2" like Haynes Roadster / +4" like McSorley plans). Also my transmission tunnel is moulded around my choice of gearbox.

There really isn't much space in these cars so you need to be clever about making the most out of it.


bonzoronnie - 15/1/08 at 12:08 PM

I thought ERW square tube was the prefered choice of material !!??

RHS of 1.6mm wall thickness, is hard to come by and not of the same fine Quality as ERW.

Ronnie


RichieW - 15/1/08 at 12:47 PM

Stick with ERW.

RHS was one of Ron's peculiarities in his book and it has continued to confuse people ever since.


Alan B - 15/1/08 at 01:00 PM

quote:
Originally posted by RichieW
Stick with ERW.

RHS was one of Ron's peculiarities in his book and it has continued to confuse people ever since.


Agreed...although ERW tube is actually a RHS product and RHS is actually welded...the RHS terminology is more for the thicker walled bigger sized box-section type products...and the ERW terminology more for the thinner walled smaller sized tubing products.

So ask for ERW square tubing....forget RHS, box etc....when dealing with the steel suppliers it will make life easier....


NS Dev - 17/1/08 at 01:05 PM

But I think his question was does he use cold rolled sheet type rhs or hot rolled sheet type rhs.

most if not all 16 swg rhs will be cold finished sheet stuff (i.e. silver not dark grey and scaly)


kb58 - 17/1/08 at 02:33 PM

Definitly use cold rolled. Hot rolled is just that and has a dark rough scale on the surface. You must get it ALL off before welding else the weld will bubble up with contaminants. Cold rolled you just clean off the oil and you're good to go.