Cantilevered shelving

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I have a bunch of 1 1/2" X 3" X 1/8" tubing I want to make a set of shelves from. All my pieces are aprrox. 39" long. If I use two of them for the upright, and lay it flat on the wall (long side) that would give me a place to drill for lag bolts as well as a place to weld the tubing for the shelves. My question is, how much weight could I expect the shelf to hold with the uprights spaced at 4' with a 39" cantilever? It would make sense to cut the tubing so the shelf is 24" deep but I don't want to waste the tubing if I can get away with a 39" deep shelf. I could also put the short dimension against the wall and put tabs on it to lag it to the studs, but I wouldn't think there'd be a whole lot of flex if it was lagged every 12" or so. I'm more concerned with the shelf brackets flexing.
Reply:1 1/2" X 3"? X 1/8"3'?A butterfly without wings, is just an ugly bug
Reply:Rectangular "tube" 1.5 inches by 3 inches with 1/8 inch wall.
Reply:39" is a pretty deep shelf with no support on the front.Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:How about like this? Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Depending how you're going to make the shelves, most people can't reach past about 30", so if they're full shelves, you'd need something like a shepherd's crook to get at stuff at the back. Just a thought but at 19.5" you get twice as many shelves.Too may possible variations, what you want to store, whether the shelves are full, long lengths of material to store or cans of paint, polystyrene, lead ingots etc...But at 39" there's a fair amount of leverage from any loading. Support brackets like Farmersamm suggested are fine but they can compromise storage space."One of the things we have to be thankful for is that we don't get as much government as we pay for." (Charles Kettering)Mitch 180 (NZ)Lincoln SAM-400-220 + ?-400 Fordson Major + 2 x Tractapac Humber 80 + Procut 40 PlasmaMiller Spectrum 375
Reply:I might go with the 19.5" idea. My garage is 28' deep so shelf size wasn't much of a concern, but I can definately go up higher. It'll be loaded pretty heavily too, so with a shorter shelf, I should have any problems with flex. Good call on that one.
Reply:I just ran some numbers and the cantilevered beam can take into the 1000's of pounds when it comes to the bending stress.  I did a rough check on the shear and it is fine as well.  This is assuming that the tube is positioned so that the 1.5" is the base and 3" is the height.  I used 36" as the length with a point load at the 18" mark.  I seriously doubt that you will be able to overload those shelves as long as your welds are sound.Rene
Reply:[QUOTE=rat4spd;226713]I have a bunch of 1 1/2" X 3" X 1/8" tubing I want to make a set of shelves from. All my pieces are aprrox. 39" longI still don't understand how they can be 39".Enlighten me please. I'm old and mis a lot. Attached ImagesA butterfly without wings, is just an ugly bug
Reply:zerepener, thanks for running the numbers for me. I decided to go with 19.5". First, it allows me to go higher on the wall instead of out farther, and second, like mentioned, I wont have to drag things from the back of the shelf.Instead of 4 shelves 39" deep and 8' long, I'll do 5 shelves 19" deep and 12' long. I'll end up with about the same space, but twice the welds.The main consideration was the load capacity though. I have a part time gig, and I keep a lot of parts at home, so the shelves will be heavily loaded.
Reply:Magnetic, these are not round. They are rectangular. Imagine a 2x4.
Reply:OOOOOOOOOOOHHHH ! I knew I missed something - It said tube I thought pipe.A butterfly without wings, is just an ugly bug
Reply:The attachment to the wall is the limiting issue.Consider a single level of shelf, 39" high, 19" deepIf the load is centered on the shelves (about 10" out from the wall), and the attchment is at the shelf height, with the 39" leg to the floor, the pullout force on the attachments will be 1/4 of the load. Example: 1000pounds on the shelf, the attachment will need to resist 250# pullout force, and the supporting structure will need to be able to handle 250# lateral force at shelf height. If the tie to the wall is below the shelf, the force it must withstand is greater. Each additional level will have similar concern. If you can run the verts solid to the ceiling height and tie in to the header, you are better off, as the verts will take the bending load (not the wall studs), and the lateral pull will be reduced (due to the long lever arm to the ceiling height) and transferred to a better load point.
Reply:That's a good point, however, I have exactly enough to build the shelves now using (2) pieces of the 39" tube per upright times (4) uprights 4' on center. I think to combat the bending force on the studs I'll sister a stud on one or both sides of the existing studs for the uprights. That ought to take care of the stud bending.