# shelf size limits for wire shelf supports?



## keytek (Jul 31, 2012)

I am planning to use hidden wire shelf supports in a closet organizer (see http://www.leevalley.com/US/hardware/page.aspx?cat=3,43648,43649&p=52465 for reference.) Does anyone have experience with how deep the shelf can be for a given size support? For instance, given an 11" support, what is the maximum shelf depth that it can safely support? Note that I'm not really concerned about weight capacity, just size.


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## Dave Paine (May 30, 2012)

These are also called "Magic wire shelf" or "Invisible wire shelf".

I have always considered these to be weak, since the shelf has a slot routed close to the front.

The ones I have experienced were knock-down furniture.

The shelf was perhaps only 3/4in deeper than the wire support.

The deeper you make the shelf, the more weight it needs to be designed to carry. Depth is weight capacity.

I would not make the shelves much deeper than the support. Heck, to be honest, I would try to use a stronger support.


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## keytek (Jul 31, 2012)

Dave,

Thanks for your reply. The reason that I'd like to use these is that I want adjustable shelves and I like the fact that they disappear (aside from the extra holes, of course.) The shelves will go into a clothes closet so I'm not terribly concerned about weight. While I agree with your comment that "depth is weight capacity", I am more concerned about the stability question raised by having shelves substantially wider than the brackets. 

As a result of your comments, I decided the best thing to do was test them. I build a test jig with a single shelf of my target depth (22"). The deepest brackets that I've found are just over 11", so there's an overhang of 5+" both front and back. The closet system, including shelves, will be built from 3/4" plywood. I loaded the shelf up with a good bit of weight (a large bench vise) and moved the weight to the front edge of the shelf, the weakest point. There was no failure over several days, so I conclude that for my use these things will work adequately. I started to get some cracking in the plywood shelf when I pushed down with a lot of my body weight. I think with 3/4" hardwood shelves, these things would be very strong.

Although I think that the single bracket would be sufficient for my use, I have decided to err on the side of caution and add a second set of brackets to spread the load more fully across the depth of the shelf. Now I'll have a total of about 17" of bracket for a 22" deep shelf.

One last point: the strength of the overall system will be somewhat dependent on the tolerances of the bracket holes and shelf kerfs, so I was careful to get both as snug as I could.


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## Dave Paine (May 30, 2012)

I had wondered if anything was happening. I love to see a test.

Your test was good, and looks like you have determined the boundaries for loads on the desired depth of shelf. :thumbsup:

The reason I am not fond of the wire supports is that less than 1/2 the depth of the shelf has to take all the load. :thumbdown:

If you are mostly interested in hiding the support, the "B" items in this link can be hidden by drilling a hole in the side of the shelf.

http://www.leevalley.com/US/hardware/page.aspx?p=40189&cat=3,43648,43649&ap=1

I saw some shelf pins which were round and flat and intended to be mounted in holes drilled in the underside of the shelf.


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## jigs-n-fixtures (Apr 28, 2012)

The other option is to use two shorter supports, say two eight inch ones per side. This gives the ability to space them to provide a twenty inch span with a gap between them.

Sent from my iPhone using Wood Forum


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## keytek (Jul 31, 2012)

Thanks, jigs.

That's exactly what I've done. My test indicated that I would probably be safe with an 11" bracket for a 22" shelf, but I decided to be safe and use two pairs on each side, giving me a total of about 18" of bracket for a 22" shelf. I think this will be more than sufficient for my application.


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