A website dedicated to the building of a VW based dune buggy and some other random stuff too.

Crazy Cam's Technical Bits... Metal

A discussion of various types of metal used in space frame chassis design.

Chassis member selection

What type of metal do I use to fabricate my space frame chassis? Most buggy builders use tube section, but most kit car manufactures (including good old Ron Champion) use square section.

Square section

• Cheaper than similar size tube
• Easy to cut - only need straight cuts - no curved surfaces
• Makes panels easier to fit - only straight sides
• Not easy to bend so need to make more cuts and more welds
• Not as strong as similar size tube
• Heavier than similar sized tube

Tube section

• Easy to bend so not as many cuts or welds needed as for square section
• Stronger than similar size square section
• Lighter than similar sized square section
• More expensive than similar size square section
• Makes panels more difficult to fit - curved sides
• Difficult to cut - ends are required to mate with curved tube sections

Crazy Cam's Solution

Build the lower chassis out of square section, and build the roll over cage out of tube.

This will provide a chassis with easy to fit body panels, where the bulk is made out of cheaper square section. The safety critical 'roll bar' sections will be made out of stronger tube, which will be better for fitting a soft top. The windscreen surround will be made from square section as this will be more simple to fit the glass to.

The roll bar will probably be a separate bolt on section allowing two different looks. (Coo - doesn't it sound like a fashion magazine) A separate roll bar section would also allow for a hard top to be added later or for different profile roll cages to be used.