I am building a kitchen rail for hanging utensils and frypans along the wall and need some help choosing the right tube size for the job.

Because I'm renting the place I don't want to drill any holes, so the rail must be one long piece of tube lying on two support legs.

Rail length needed is 2.5 meters or 103 inches.

There are few sizes of alloy square tubes I can easily get in Sydney are:

  • 20mm x 3mm - 0.787" x 0.118"
  • 25mm x 3mm - 0.984" x 0.118"
  • 25.4 x 1.2mm - 1" x 0.047"

(I grew up in the metric world and did all conversions to inches in google calc, sorry if the numbers look awkward)

I think overall I'll be hanging 5-8kg or 10-18 pounds of stuff, distributed mostly along one half of the rail.

What formulas should I use to calculate the size of the tube needed, or the maximum weight a particular tube can support?

Would circular tubes be stronger in this application? If yes, what are the formulas for circular tubes?

  • There are equations out there, but they take more than the length and thickness of the tube (they actually need to know more about the metal and it's strength). But for a 20 pound load, you are going to be safe with the 3mm thickness and probably even the 1.2mm. Since life and limb don't depend on this, just see how stiff they are in the store and base your need on this. – diceless Nov 6 '14 at 5:33
  • Thanks for your comment - metal is alloy 6060T5 and I can google all its properties, but formulas involve quite a bit more research. When I tried it in store any tube would bend slightly, maybe that's not a big deal, maybe it is. However, what I want to find out is whether or not it'll be a problem with load applied over many days. That's hard to test in store. – Paul Nov 6 '14 at 10:59
  • 2
    @Paul - It seems that you are thinking about this way more than necessary for the small load that you are anticipating. Select the largest size tubing that looks decent and go with it. I think the issue that needs your attention the most is the stand-up supports so that they stay in place and are designed with triangular bracing to the horizontal tube. – Michael Karas Nov 6 '14 at 13:06
  • You might want to double check your weight, that's an awfully big rack for just 5-10-kg or 10-20-lbs. But, any one of those options should be overkill. However, if they're the look you want you can use them as covers over smaller diameter steel pipe, round or square, to really remove any doubt. – Iggy Jan 18 '16 at 20:53
  • If all those tubes are steel, they'll all work. If you're super concerned/fancy, you can even mount it on a corner (rotated 45°) so the MOI is increased even more. If they're aluminum (or aluminium, but I reserve that for the element only), then I'd be concerned by the thinner wall thicknesses. In the metallurgical world, almost everything is "alloy." – Hari Ganti Feb 25 '17 at 0:02

You could accomplish hanging a total of 8 kgs of pans on a 2.5 meter long tube of 25.4mm diameter x 1.2mm thickness. I assume this is the cheapest option, but it might be more susceptible to failure in the long run than your other listed options. Supposing that it was mounted well, it could withstand a good amount of static force... based on my familiarity with materials. I'm a scientist and I'm darned good at physics, but this question is more about familiarity with materials and kitchen rough-housing.

Generally, 2.5 meter a tube that is 25.4 x 1.2mm will hold your 8kgs of pans, but the 25mm x 3mm tube would destroy the 25.4 x 1.2mm in a "sword" fight. And although the 20mm x 3mm would probably beat the 25mm x 3mm in a sword fight, the 20mm diameter would not necessarily win the load bearing contest against 25mm pipe. So they are about equal except the smaller diameter tube should be a litte less susceptible to dents... it's probably more of an aesthetic choice for size.

If the prices aren't very much different, the 20mm or 25mm x 3mm will be about 6 times stronger than the 25.4 x 1.2mm. Also, you want to have a good stainless steel in the kitchen, like 316.

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