The Home Machinist!

Assuming 1/8” wall and oriented the same way, what size rectangular steel tubing would be roughly equivalent to a 2x4?

I have built and helped build a bazillion things out of wood over the years and know when to use a 2x4 vs a 2x8 or 2x6 etc. for non life critical applications. Benches, sheds and such. Now I’m trying to get a feel for napkin engineering things from steel around the house for something different but I need a reference point. I know there are load charts and all sorts of calculations that I could look up, but if I were building something that critical, I would probably have a pro do it instead. I’m just tinkering.

Anyone have a general rule of thumb they use?

Griz

Several years ago, a relative of mine was in maintenance at a paint company when they got rid of shelving that held heavy skids of gallon paint cans.

He gave me several dozen of the ~ 10ft long rectangular tubing that held up those loads.

They are almost the exact size of a wooden 2x4 and are 1/8th inch thick. I use them for all kinds of projects, as can be seen in the U-Tube video below.

https://www.youtube.com/watch?v=cu7Cou5zVi0

Made two of those TT frames, and I'm now welding up a bridge frame out of the same tubes. Easy to weld. I was real fortunate to be given such a gift.

If you can find used shelving of a similar type, that may be much cheaper than buying new.

Very cool video! I’ve always been impressed by the dedication of scale railroad builders.

I don’t have a particular project in mind right now, I’m just trying to find a reference point should one come up.

Thanks for the explanations! I'm new to metal working and would like to learn how to do a scale warship model out of metal, and I've got trouble finding reliable data about strengths etc... I'm a complete newbie and you guys are very informative, sorry if I end up asking stupid questions!

You need to remember that a smaller tube will hold as much as a 2x4 in a vertical position but as a beam it may have less strength. There are tables that give the safe working load for lumber and steel both as a post and a beam. Do some internet search's.
Mike N.