Flexy rack for 160 pound TV - doubled 3/4" shelves and 3/4" rods?

Discussion in 'Home Theater Projects' started by MichaelDDD, Feb 27, 2004.

  1. MichaelDDD

    MichaelDDD Supporting Actor

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    Hi all,

    Until I can save up enough for the Hitachi RPTV of my dreams, my 32" Sony will have to do. :b

    The entertainment center it's in has gotten old...it's been moved a lot and is getting wobbly. Aside from that, I want to make a separate rack for the AV gear.

    Anyway, the TV weighs 160 pounds. Sony's are absolute beasts!!!

    I am pretty sure that I'll need to double-up the 3/4" MDF to make double-width shelves, but what about the threaded rod?

    3/4", right? I don't think 5/8" would be enough.

    This is going to be a three-shelf stand. TV on top. Middle shelf for stability (to keep the rods from "wiggling") and bottom shelf b/c you need one! [​IMG]

    Whataya think?
     
  2. Robert_CA

    Robert_CA Stunt Coordinator

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    5/8 dia. rod will do nicely! It's pretty stout stuff even for the 160 lb. Sony. I used 5/8 dia. rod for my flexy shelf that supports my 60+ lb. Adire LCC over my 46" Mits RPTV. To minimize sagging, I rabbitted on a 1x2" span of oak facing across the span and encased the rods with 1-1/2" dia. PVC conduit wih flat washers and hex nuts on the I.D. of the PVC. My 1" thick shelf is over 47" wide and sits on 49" tall rods and it seems to be holding up just fine. Since you're using other shelves underneath, you will have plenty of lateral support. Are all your shelves 1" thick? If so, that flexy rack is going to be a heavy one!
     
  3. MichaelDDD

    MichaelDDD Supporting Actor

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    Hi Robert,

    I've never been able to find 1" MDF anywhere...only 3/4". So that's what I'll be using; 3/4" MDF.

    I would think 1" MDF would be plenty strong, but I don't know about 3/4". Having my TV crash to the ground and explode would....well, just suck, you know? [​IMG]

    It would be nice if I could use the 5/8" rod b/c the 3/4" is a lot more expensive.
     
  4. Bob Kavanaugh

    Bob Kavanaugh Second Unit

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    I used 3/4 MDF and 5/8 allthread, and there is no sign of warping or sagging. My TV is every bit as heavy as yours, plus when my 230lb stepdad saw it he SAT on it, and said "hmm, this is pretty sturdy". See the link in my signature.
     
  5. MichaelDDD

    MichaelDDD Supporting Actor

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    Bob, your rack looks great! Waitaminute...that sounds funny. [​IMG] Hahahah!

    Seriously, you did a great job. It's obvious you planned it out very well.

    Did you clamp all the boards together and drill all the holes at once? How did you get the holes for the rods all perfectly aligned "in between the edges" in each corner?

    The first pic on your index page says it all; you have way more equipment on there than I will and if your holds, so should mine. Also, the fact that your..um...large, stepdad sat on it and it's still here today is another good sign. [​IMG]

    5/8 allthread is about 1/2 the cost of the 3/4" stuff. That's a good thing as well.

    Thanks, Bob.
     
  6. Robert_CA

    Robert_CA Stunt Coordinator

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    My shelf is 3/4" MDF and 1/4" oak veneer plywood. As to the sagging question, any material (including steel) will sag or flex if a heavy enough weight is placed on top of it. That is why lumber will sag to a greater degree when loaded on its face as opposed to it's edge. Builders use OSB or oriented strand board to fabricate floor joists for home construction that is lighter but as rigid as joists made of 2x10 solid lumber. They can accomlplisn that because the "trands of wood are "oriented" to be most rigid controlling factors are the structural rigidity of the material and the width of the span between the supporting structures. You will be O.K. however with a 1-1/2" MDF shelf and a short span.
     
  7. MichaelDDD

    MichaelDDD Supporting Actor

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    Thanks Robert, I'm thinking that if I design the rack with rods in the middle of the shelves as well as in the corners (like Bobs') I should be OK with 3/4" MDF.
     
  8. MichaelDDD

    MichaelDDD Supporting Actor

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    Bob K

    I just noticed something; the middle rods don't go thru the top shelf. Does the top shelf just "sit on top" of the middle rods?

    I don't think it would look that bad with the rod going thru the top shelf...I'm very neurotic about that kind of stuff...I've gotta do the job right the first time.

    Did you plan it that way? To have the middle rods not go thru?
     
  9. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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  10. Robert_CA

    Robert_CA Stunt Coordinator

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    I beleive that you could use a forstner bit to drill about a 1/4" deep hole into the underside if the top shelf to embed the rod and hex nut for the middle all thread support. I makes for a cleaner look. If it were me, I would extend that middle allthread rod all the way to the floor (with feet) to transfer some of that load. In the picture it looks like that lower shelf was possibly sagging a little. Others have used this technique because they have often placed their heavy 5 or 7 channel power amps on those lower shelves. With your Sony on top, the load will still be transfered through those middle rods downward to the lower shelf.
     
  11. MichaelDDD

    MichaelDDD Supporting Actor

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    Robert_CA,

    Excellent suggestion and very good points. [​IMG] Thanks much!

    My "rack" will be more of a "stand." It's only going to be 18-24" tall. Just enough to get the TV up at a decent viewing height. [​IMG]
     
  12. Dennis Gardner

    Dennis Gardner Stunt Coordinator

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    3/4" mdf starts to sag if spanning gaps approaching 40 inches with the weight you plan. If you don't like the look of double shelves, you could put 2 inch wide straps of 1/4" steel spanning between the posts underneath the top shelf. You could also puts rods between your middle
    rods just behind the screen where your TV narrows in the back extending to the floor,if it is like most normal direct view sets.

    Good luck,

    DG
     
  13. Justin Ward

    Justin Ward Supporting Actor

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    Check out the pics from my flexy if you want some ideas or something.
     
  14. MichaelDDD

    MichaelDDD Supporting Actor

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    Thanks Dennis and Justin.

    Justin, nice work, man! [​IMG]

    I already have one idea I'm stealing...er...borrowing from you. Putting the center channel on the shelf underneath the TV.

    That'll put my center channel almost even with me L/R speakers tweets. Within about 12" actually! Should sound great. [​IMG]
     
  15. Bob Kavanaugh

    Bob Kavanaugh Second Unit

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    Michael, sorry for the late reply....

    To get the holes aligned perfectly, I used a marking guage and scratched a line 1 1/2 inches or so from each edge, and where they meet is where you drill.

    The middle rod does not go through, because a nut would block access to the front controls, it is supported though, by the nut and washer underneath.

    Thanks for all of the compliments, I really like my flexy.
     
  16. Arthur_King

    Arthur_King Stunt Coordinator

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    I cant for the life of me find the link to it, but I saw a couple of flexy racks that had essentially 3 layers to them. One I did find and is easy to find is the Flexy+. Though I dont know if that unit really would add to the structural weight bearing capacity, it sure is nice [​IMG]. The other one, and the one I cant find, used either a 2 inch piece of MDF or a 2x4 frame sandwitched between 2 pieces of MDF (hence the 3 layers). from the side it sort of looked like this.

    --------------
    || hollow ||
    --------------

    the --- being MDF and the || being a 2x4 frame made slightly smaller than the outside of the MDF. The Rods would go up through the MDF and probably (I cant remember) also through the 2x4 frame.

    Im sure the 2x4 in conjunction with the MDF would give you TONS of structural integrity and have no problem holding up 160lbs. I would recommend going with as large a threded rod as you can get away with, Ive seen up to 3/4" threaded rod at Home Depot, and if you can find all the parts (metal/rubber washers, hex nuts, PVC Pipe, etc) I would go with that. Better safe than ending up with a bowed ugly shelf or worse a TV face down on the floor [​IMG]

    Daffy Arthur King
     
  17. Allen Ross

    Allen Ross Supporting Actor

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    nice sig Arthur truer words have never been spoken

    As for the flexy, i wouldn't go much over 24 inches with out a support with 3/4

    my flexy supports my full weight, i gave it the "earth quake test" and holds my custom rack mount (55-60lbs) with out a problem.

    heres a link to the finished flexy

    linky
     
  18. MichaelDDD

    MichaelDDD Supporting Actor

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    Arthur and Allen,

    Thanks much for the input.

    Allen, your rack looks more than sturdy! I know that top 19" rackmount is heavy. Good stuff, man.

    Arthur, that link...is insane! [​IMG]

    That thing has got to weigh 200 pounds, easily. It's just a wee bit beyond my carpentry skills. [​IMG]

    It sure looks nice though.

    That MDF/2x4 sandwich would support anything, I'd wager.

    I'm also of the "better safe than sorry" school. Better to overbuild.
     
  19. Allen Ross

    Allen Ross Supporting Actor

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    I bet you say that to all the members here
     
  20. marc_manny

    marc_manny Stunt Coordinator

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    I built a Flexy almost exactly like Bob's. I used 5/8" threaded rod. For the center support I put flange nuts under the top piece of MDF. Mine supports a 160 pound sony TV.

    Flexy

    Flexy

    Marc
     

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