RHS is not what you would call square and usually twisted where the ERW is precision tube.

The 1.6mm ERW was chosen because it's strong enough to do the job and it's light. Using RHS would make a strong and heavy chassis but it doesn't deform in the same way as ERW in an accident, the progressive collapse by buckling is preferable to joints breaking and possibly pushing tubes into the passenger compartment.

Cheers

Chris :)

Thanks for clearing that up Chris. Whats the cost difference between ERW and RHS?

i paid £9.70 per 6mtr for 25x25 1.6 and
£7.40 per 6 mtr 19x19 1.6
plus £15 delivery , i think total was £115ish
this was ERW

andy

Talk about bargain prices. May i ask who your steel supplier is and how far a field will they deliver to?

i haven,t got the receipt with me at mo ( its with my chassis, being built at mothers place), i,ll get you the details tomorrow & post it on here, not sure how far they deliver but imagine they would to your area,
they don,t hold the steel in stock, they are like a stockbroker, you place the order & they get the best deal for you.
the above prices included VAT too, as i said i,m building to strict budget :D ;)

andy

ok guys im gonna throw a big spanner in the works. the book states 16gauge box section. 16gauge is 0.0598inch thick so actually its 1.51mm.

sorry just being silly tonight

i dont know what your faffing about my arc welder will weld up 16gauge no problem. the trick is to strike the arc on the corner as its the most heat resistant bit.

The more you buy the cheaper it will be so why not get a few of you and do a "group buy" on the tube?....:D

Ahhhhh..... That will be the nominal thickness :D :D :D :o

So just to make sure, it will be 1.6mm, not 1.5?