Thread: Strength difference

Go for the heavy one every time, you won't regret it. I personally wouldn't use any thing less than 3mm, most of the time where I work we use 4 and 5 mm rhs routinely.

Robert

The weight difference is only 1040gram per metre so you might as well go the extra.
Metaland have a book you can download which among other things lists the weight per metre of each size.

Yep second that. The Metaland book I got stays in the ute. Really useful reference.

Originally Posted by Wombat2

Is there much difference in strength between 2.5mm and 3mm 100x50 RHS being used for a trailer drawbar?

The two numbers for the bending capacity of these two sizes of 100x50 RHS are:

3.0mm - 21.3
2.5mm - 18.2

This indicates that a 100x50x3.0mm will have approx 17% more bending capacity than the 100x50x2.5mm. Keep in mind that going from 2.5mm to 3.0mm is an increase of 20% so while it is 'only' 0.5mm it is a large increase.

Other things are considered when looking at capacity tables for these members but it's still a good comparison of relative strengths.

I considered using 75x50x3 RHS or even 65x35x3 RHS for my new 'yard' trailer but in the end I calculated it was only going to save 20-30kg in total trailer weight compared to the 100x50x3 RHS I planned for the camper setup that would follow. In the end both these trailers will have essentially the same chassis of 100x50x3.