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I'm planning on rigging a shelf which is 18 mm sheet of OSB.

Can I just pass a cable through a grommet -protected hole in the board? Would it hold?

The sheet is 1.5 * 1.2 meters, how much space from the edge do I have to leave for each of the four points of rigging?

Basic illustration -- I want the cables to be slightly non vertical, so that the shelf would be more stable laterally.

Specifically what kind of grommet would I need. Or should I call it hollow rivet. I know I'm constrained by the radius of wire bending to be 10 times the wire diameter.

What's the required diameter of the rivet to hold reliably in the board. Does it need to go through whole thickness of the board, or would, say 10 mm be enough? Would threads on the rivet(making it hollow screw) be beneficial? What's the diameter of outer flange required to hold the grommet from being pushed into the board.

The shelf is supposed to hold 50kg overall(not necessarily evenly distributed), that makes ~250N of horizontal force pushing the grommet laterally. And up to 400N of force vertically.

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    Please tell us more. How heavy will the load be? Will the cables be hanging vertically or at an angle? Does the grommet have threads in contact with the OSB or does it have a bottom flange? How will the cable actually connect to the shelf? – Ashlar Feb 16 '16 at 20:17
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    Would it hold WHAT? – micmcg Feb 17 '16 at 5:10
  • There are several comments about shelf sagging & shifting under load. I would think that if you used longer cable to run diagonally under the board, that would likely resolve, or at least reduce, both issues. – FreeMan Mar 21 '16 at 15:07
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I don't see any reason this wouldn't work as long as the loads on the shelf are reasonable (both the total weight and the placement of any heavy individual items). The OSB is going to be quite strong at 18mm and the portion of the cables running under the shelf will act very much like a conventional shelf support, albeit very narrow ones.

The weak point in OSB is the cut edges, which can be a little flaky or friable, and the grommets should take care of that.

The sheet is 1.5 * 1.2 meters, how much space from the edge do I have to leave for each of the four points of rigging?

I'm not sure it makes any difference since the board material outside of the holes won't be involved in taking any of the load or other forces exerted on the shelf.

I'd probably go in from the long edge approximately 15cm myself and more from the shorter edges, purely for reasons of visual balance, I honestly don't think it matters at all.

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    Depending on loads (which OP has still not clarified) I would have thought this to sag over time and should have some supporting braces to mitigate bowing across the length of the board. – Matt Feb 17 '16 at 13:35
  • @Matt, sagging is always a potential issue with any shelf. The load — and critically, how it is distributed — makes all the difference, there can be a cantilever effect (?) from stacking at the ends which directly counters bowing in the centre. – Graphus supports Monica Feb 18 '16 at 20:26
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Grommets should provide adequate protection for the hole provided they have a bottom flange capable of supporting the OSB board. I would not recommend a threaded grommet without a bottom flange.

There are however, several other design issues to consider:

The 18mm/3/4" thick OSB will begin to begin to sag between the openings if the board is not reinforced. I would recommend using a 3/4 x 1 1/2 (18mm x 36mm) wood edge trim around the perimeter (Long leg vertical) glued and nailed to the the shelf panel.

The cables may need to be secured to the shelf panel to prevent the shelf from shifting from a horizontal orientation. Although the shelf position may be stable due to the friction of the cable to the grommet, if the shelf is bumped or lifted at one side, it may slide out of level. You can test this potential risk when you first hang and load the shelf.

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