Mounting a 16" deep box on wall

[radhak]

A friend of mine came over today - he had a plank of pine 16" wide : he wanted a box to hold his DVD player + Cable box. Took me some minutes to cut his pieces out for a box of dimension 16" deep x 10" high x 26" wide. I also butt joined them with glue/screws for him and he said he'd add a back of 1/4" thick cheap ply.

Then he tells me he wants the box to go up on the wall, but he does not want visible brackets underneath the box. He wants some sort of a hidden support. I told him to get some hardware that'd go on the rear-edges of the sides, but added that those hardware might be insufficient to hold a 16" deep box. The other suggestion I had for him was to not add a back, but put brackets inside the box, supporting the top and anchored to the wall. But of course, he also wants the back. He believes he's got the solution : he wants to add the back, then secure the brackets inside the box, anchored to the wall thru the back and also screwed to the top.

So - is he right? Will it work? And is there a better way to also have the back and yet secure the box to the wall with no brackets underneath? Eg, if he uses another pine piece for the back (3/4") instead the thinner ply, could he just screw the back to the wall and be done with it?

[eccentrictinkerer]

I just hung some shelves for a an artist here in Minneapolis. He also wanted no visible hardware. I built a jig to drill 3/8" holes into the back edge of the shelves and into the studs behind the shelves.

I then cut the heads off some 6" long 3/8" lag screws and screwed them into the wall with a Vice-grips. Hammered the shelves onto the lags and "Bob's your uncle"!

You can noodge the shelf level with a few well-placed hammer blows when the customer's not around.

These shelves were only 6" deep and held only family photos, but I've used idea for all sorts of shelves.

[LCHIEN]

Rad,
you have to think of how this unit might fail.

By placing the brackets on the bottom then the load of the cabinet is compression on the sides - wood and wood fasteners hold well in compression. But, he doeesn't want this.

Screwing the ply back into the wall will fail because the weight of the cabinet will want to pull the cabinet forward, pulling the fasteners that hold the back to the cabinet frame. 1/4" ply would be insufficient to retain these fasteners into the edge of the frame.

His idea of putting brackets inside will work to some degree. I assume the brackets will be on the inside of the cabinet, trapping the back ply between the bracket and the wall studs. The top of the bracket can be fastened to the bottom of the top of the frame supporting the top.
Now the only weak point is the way you have the sides fastened to the top and the bottom fastened to the top - these will be in tension and should the fasteners pull out the bottom of the box will fall.

If the load *DVD and cable box) is relatively light and no one will lean on it then it may be OK. I don't knwo wheter you use nails or screws, and how many, all key factors. Another way is to use better joints but its probably too late for that. A third improvement would be to fasten a 16" long 1x1 type member on each inside corner and screw the top, sides, and bottom into these - would make me a lot more sure about holding under tension because these fasteners for this step would be in shear, not tension (e.g. the nail or screw would have to be broken as opposed to just being pulled out).

[cgallery]

I'd glue & staple the back on (1/4" ply should be okay--they rarely use more than this for kitchen cabinets which support heavy loads), then add a cleat to the inside top of the cabinet. I'd run screws through the cleat, through the 1/4" ply back, into studs in the wall.

[Stytooner]

French cleats would work great for this. The back could be attached to the inside of the cleats. Mount opposing cleats on the wall, then just hang it on there. No visible hardware. Strong and easy to remove.

[cabinetman]

The trick to this project lies in the fact you have already assembled the box. French cleats will work, and so will a solid back of 3/4 ply. If the box is together, you could rout the inside back edge (rabbet)for a solid back, and/or french cleat, and glue it in and fasten the back from the back into the top, bottom, and sides with pin nails or staples, in addition to glue (it won't show). Then find the studs, mark the back where the studs are, and predrill holes from the back, to screw it through the back.

If you use a back and a french cleat, you'll have to rabbet a depth for the thickness of the back and the cleat (usually 3/4" for the cleat). I usually rabbet an extra 1/8" deep so the cleat won't bottom out, and that it will insure the edges of the box will seat on the wall.
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[crokett]

I'd go with french cleats. My shop cabinets are not 18" deep but they hold a lot more than a DVD player and cable box. They are hung on french cleats.

[radhak]

Great options to choose from, Thanks everybody.

While the box is already assembled, the back is only screwed on (I hope), so I'll talk to him. Thing is, he's the typical reluctant diy-er : just want's to be done with it, with a blase attitute to the risk he'd take with a half-baked approach. (He wanted to stain and finish the pine; when I told him he'd need to sand it a couple of times, he immediately jumped ship and planned to paint it .

But for my edification : how would the french-cleat work without a back, or even with a thin back? I'd thought it'd need a full-thickness back for strength when attached to the cabinet, else it'd just be fixed to the sides, which would mean less strength, wouldn't it?

[LarryG]

In visible locations, French cleats are usually inset into the cabinet back, so that the edge of the cabinet body and the face of the cleat that mates to the wall are all nominally in the same plane. This prevents the unsightly gap that would occur between the cabinet body and wall if the cleat were surface-mounted. In this inset scenario, the cleat is supporting the top panel of the carcase. Assuming good, solid construction and normal loads, that's adequate. If there's a back -- even a thin one -- the cleat can (should) be glued and possibly screwed to it (screws driven from the inside), for even more strength.

[cabinetman]

A back isn't necessary to use the french cleat system. If the rear of the cleats are lined up with the cabinet edge, the possibility of a high spot on the wall will stand the cabinet out from the wall. I recess the back side of the cabinet cleat to allow the edges to touch the wall, and allow some scribe if visibility is a concern. It also keeps the cleats from bottoming out and not seating completely. In other words the back of the cleat and the cabinet edge are not on the same plane.

In installing the pieces, they are cut the dimension of the interior width, as both will wind up inside the cabinet. To make it simple, cut the stock the width of both cleats, at a length of the interior of the cabinet. Then, cut a 45 degree rip along the length in the middle, yielding both members of the cleat.

Since you may be only able to catch 2 wall studs, the wall member should be tall enough to accept 2 screws at each stud location.

The cabinet member can be attached to the underside of the top and the two sides with glue and fasteners. once the cabinet is hung on the cleat, the bottom member of the cleat will be the one that is mounted on the wall, with the 45 deg pointing away from the wall upwards. Cutting both pieces from one will give a more uniform appearance to the cleat as viewed from the front...the grain and pattern will be continuous.
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[radhak]

Thanks Larry and CM : very clear instructions. Now I want to go to his place and do it the right way myself, whether he wants it or not .