Shelf_Brackets.txt
Posted 12/17/04 by Andy Wakefield

I needed some heavy-duty shelf brackets to store some steel ... but once I made the first set, I kept thinking of other uses for them around the shop. The brackets shown in these pictures are some of the latter and were made out of scrounged bedframe angle iron, but they are basically the same design as the ones I used to store the steel. Bedframe raises some of the same questions as rebar, in terms of the possibility of some brittle welds due to uneven carbon content. In addition, this material is only about 1/10" thick -- but it is 1-1/2" wide on each side of the angle. As you'll see in the pictures, I turned the material to make a triangular cross section (i.e., using like a V rather than like an L). I don't know whether that enhances the strength or not, but intuitively it seemed to have advantages, particularly in terms of resisting twisting. (My intuition may be wrong, of course!) The use of the triangular brace adds a great deal of strength to the structure, meaning that I'm asking a lot less of my welds -- there should be no twisting forces applied to the welds, just compressive and shear forces. (I think!)

Note that in all of these pictures, the brackets are shown "laying down" -- the flat bar that is on the bottom in these pictures will be set against the wall/stud. When I talk about the "horizontal support" below, I'm talking about the piece that *will* be horizontal when they are mounted. In these pictures, the "horizontal support" is actually vertical, but hopefully you get the idea.

Dimensions: The horizontal support is 1-1/2" x 1/10" angle iron, 16" long; the triangular brace is 1-1/2" x 1/10" angle iron, approximately 14" long; the back plate is 1/8" x 1-1/2" flat bar, 14" long.

Shelf_Brackets_1.jpg -- this shows the basic design. In this picture, the pieces have been tacked together but not fully welded. There are three holes in the back plate for mounting to a stud with lag bolts; the top hole is above the horizontal support, so it is hard to see in this picture (you can just see the edge of it on the second bracket). Note also the hole in the end of the horizontal support -- this is for mounting a bolt if needed to provide a "lip" to hold things on the shelf; I've also used it for a screw to hold a wooden shelf in place.

Shelf_Brackets_2.jpg -- this is a close-up to show the detail where the triangular brace meets the horizontal support. (If the bracket were mounted on the wall, this picture shows what you would see if you were standing directly under it and looking straight up at the point where the triangular brace meets the horizontal support.) Note how the brace "cups" around the horizontal support, to provide both lots of weld area and lots of support. Note also that the angle at which the brace meets the horizontal support creates the effect of a v-groove, allowing good penetration in the weld.

Shelf_Brackets_3.jpg -- this is a close-up to show the detail where the triangular brace meets the back plate (the mounting plate). Again, the angle at which they meet creates the effect of a v-groove, allowing better penetration in the weld.

Shelf_Brackets_4.jpg and Shelf_Brackets_5.jpg -- these show one bracket after it is fully welded. (They are more or less identical shots, but the first was taken with the flash and the second without; I can't decide which lets you see the details better, so I've included both.) The welding was all stick welding, mostly using 7014 rod -- this is the only project I've ever done where 7014 seemed to perform better than 6013. I couldn't seem to find a heat setting that made 6013 weld properly without wanting to burn through. I also used 6011 as a first pass where I didn't get the gaps nice and tight. (I was out of 7018 at the time; otherwise I would have tried that.) Overall, welding these seemed a little more tricky than some projects I've done, and the resulting welds do not look as good as my better efforts -- maybe because of the bedframe material?.

Shelf_Brackets_6.jpg -- the brackets after painting with glossy black spray paint.

Shelf_Brackets_7.jpg -- three of the brackets in use to support a large wooden shelf where I now store a lot of "junk" that use to reside on the floor!