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Hi everyoneI am planning out a new welding project to build an entertainment stand for my AV equipment and TV. I want it to be minimalist but it needs to be hefty enough to support the weight of my equipment and especially the TV. My 47", 60# LCD TV will be mounted to a articulating arm that will be able to swing out and turn from side to side. The articulating arm will be mounted about 4' high and all of my AV equipment including reciever, amplifiers, computer and other equpment will be mounted under the TV on racks. I figure each rack needs to be able to support 50# each to give a little headroom.I am building it using mild steel that will be painted black. I want the rack to be as non-intrusive as possible.This all brings me to my basic question. How do I figure out how thick of material I should use? How do I determine if a particular configuration is strong enough or if it should be re-enforced or redesigned? I know that 3/16" material is overkill. But will 1/16" be too thin for two angle iron supports?Does anyone have any good referrences that could help me do some design calculations?
Reply:What shape is the material?Thickness of the material is only one consideration. The shape and size of the shape and orientation of the shape have alot to do with the overall strength of the structure. A rectangular tube with the long side aligned with the direction of the force is much stronger than if you take the same size and thickness of rect tube and turn it so the short side is taking the load. A tube with a larger diameter can have a much thinner wall thickness and support the same load as a much thicker tube with a smaller diameter. A round, square or rect tube can have a thinner wall thickness than an angle or c-channel and support the same load equally because the completed perimeter shape of the tube is inherently stronger than the open shape of an angle or c-channel. The orientation of a channel affects its strength as well. If the web is aligned with the load, the channel can take more load than if it is turned so the legs are taking the load. An unequal-leg angle can be oriented to take more or less load too. Same with an I-beam or h-beam.I had a set of audio equipment rack rails for a project that never happened. I still have them around here somewhere but cant remember where I put them. As I remember it, the rails were about 12 ga or maybe 10 ga cold rolled steel and the shape was an unequal leg angle about 1-1/2" by 3/4". This is all from memory, so you may want to head down to your local Guitar Center and check out equipment rack rails and make a note of the dimensions. The rack rails are designed to be oriented vertically and mount amplifiers and the like by the side ears at the face of the equipment body. There is a downward force as well as a torsional force exerted on the rails by the equip mounting from the face. Heavier equipment uses a second set of rails that mount to the rear of the equipment case but most of the equipment can be mounted just by the front ears and work fine. As I remember it, the longer side of the angle was in line with the torsional force and mounted to the rack walls and the equipment mounted to the shorter side.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:This "Rack/Shelf" that I made for our Vans is made from 1/8" Angle and 16g 1"x1" tubing.The middle shelf supports 405lbsTop shelf supports 100lbsEd 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:Thank you for the replies.Here is a general idea of what I have sketched out:If you look at the rack from the side, its basic shape is like a capital "E". The main support or spine on the back will be made up of two 1" X 2" square tubes spaced about 1 ft apart. At the top of the spine will be mounted the swivelling TV mount with the TV. Each shelf will be supported by two pieces of angle iron bolted to the spine. The shelves themselves will be 2 ft X 4 ft, made of a 1/2" square tube on the long side and expanded steel grating stretched and welded to the square tubing.Here is a rough side view of what I have in mind:I think it is a simple design but I can tell there will be a lot of stress where the shelf support angle irons meet the spine. I'm not sure how much extra support I should put there.I will be TIGing all the welds and I'm going to make it more of a challenge by using no fill rods. So everything has to fit perfectly.TV mount:http://www.monoprice.com/products/pr...seq=1&format=2
Reply:Sounds like a good project.You're going to need to fill your weld joints to size with filler rod to have an appropriately strong joint for the material size being used. Going with no filler, your weld joint will be undersized and thinner and inherently weaker than the base metals used in the structure.An appropriately sized fillet weld has leg lengths equal to or greater than the base metal thickness and a flat or slightly convex face profile. Or you can go by the throat dimension, which is the depth of the weld from the root to the face at an angle midway between the horiz and vert legs of the joint (45* for a 90* t-joint). Throat should be equal to or greater than the base metal thickness. If the leg lengths are smaller than the base metal thickness then the weld is underfilled and not equally strong with the base metal. Where there are base metals of differing thicknesses used in the joint, the weld should be sized to match at least the smaller of the 2 base metal thicknesses.An appropriately sized butt joint is fully penetrated at the root through to the under surface of the base metals and filled flush with the top surface of the base metals. You're not going to accomplish that without some gap in the metal (a groove joint) and using filler to fill the gap. If your weld is insufficiently penetrated and/or insufficiently filled, your weld will be thinner than the base metals and inherantly weaker than the base metals.Personally, I would use the same rectangular tube for the whole project just for consistency of appearance and ease of fabrication, as well as better use of all the material (less scrap). Theoretically, you want a larger diameter and/or thicker wall tube for the bottom legs and verticals than for the shelves, if you want to save material weight/cost going into the project, but using the same size all over is acceptable as long as it is sized sufficiently for the bottom legs and verticals, as they are subject to more load than the shelves.1x2x.065 rect tube, oriented with the long side vertical, joints welded on all sides, should be sufficient for the shelves.1x2x.120 rect tube, oriented with the long side vertical for the legs and long side facing the side for the verticals, joints welded on all sides, may be fine, depending on how much weight is being supported. You may want to go up to a 2x3x.120 tube size for the verticals and bottom legs if your stuff is heavy.You may want to put 45* supports between the legs and verticals about one foot out, using the same material. If you have a heavy amplifier going on the bottom shelf, you may want to drop a vertical leg down from the ends of the bottom shelf tubes to the ends of the bottom support legs on the floor.I would space the pair of verticals and legs at about 24" apart instead of one foot apart so the rack will have more stability with the legs wider than the equipment being held and use wood or glass for the shelves.Last edited by DesertRider33; 09-01-2009 at 12:27 PM.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Here's another thought. If you dont want to weld the shelves in place, you could weld some approx 4" long pieces of 1x2x1/8 angle at 90* to the shelf tubes and bolt them through the side of the 1x2 vertical tubes. This would eliminate any problem with warping the vertical tubes due to all the shelf welds being on the same side of the vert tubes.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by DesertRider33You may want to put 45* supports between the legs and verticals about one foot out, using the same material. If you have a heavy amplifier going on the bottom shelf, you may want to drop a vertical leg down from the ends of the bottom shelf tubes to the ends of the bottom support legs on the floor.I would space the pair of verticals and legs at about 24" apart instead of one foot apart so the rack will have more stability with the legs wider than the equipment being held and use wood or glass for the shelves.
Reply:Also, I'm trying to use minimal materials to make the entertainment stand look elegant. It is not to save on materials.I already have some of the materials:20' of 1" X 2" X 16 guage square tubing (verticle supports and main legs)4' X 8' expanded metal grating (shelving material)20' of 1/2" X 16 guage square tubing (shelving ends that the grating will be stretched over)I just lack the 1" X 1/8" angle iron for the shelving supports and some other odds and ends such as nuts, bolts and what I'm going to use to re-enforce the shelving supports.
Reply:I did not realize you were intending to make it 4 feet wide, I thought it was going to be one stack of components rather than two. In that case, I would use three vertical supports and bottom legs, one on each end and one in the middle between the two stacks of components.My suggestion for the 45* supports was not for the shelves. I think the shelf tubes will support themselves using the rect tube welded all the way around to the angle bracket and the angle bracket bolted to the vert columns, or with the shelf tubes welded directly to the vert columns. Where I was talking about putting the braces was on the bottom between the bottom legs and the vert columns. With 4' of length and 20" wide components, there is enough room to space the ones on the bottom shelf apart a bit in the middle to allow for the 45* braces on each side and one in the middle, one on each column at the bottom, none on the shelves. I say this because the column tube size is both small and thin and all the load is on one side extending out far from the columns. There is quite a bit of stress at the bottom tube to column joint. These joints in the structure would greatly benefit from 45* bracing using the same rect tubing, which will transfer some of the load higher up on the columns and further out on the bottom legs and overall make the structure stiffer.I don't have a nice drawing program to illustrate what I'm talking about and sometimes it's hard to describe designs with words so sorry for any confusion.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Something like this, except without the periods going horizontally. I had to put those in or the computer wouldn't let me put the \ lines in the right places to make it look like a 45* brace.||____________________ |
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发表于 2021-9-1 00:43:48
