Shelf Cabinet With No Back


I'm building a narrow-tall shelf for a friend. Using three-quarter inch ply. It's over 8' tall and about 21" wide. About 7or 8 shelves which I'm dadoing into the sides. The friend doesn't want a back on it though and I'm afraid the whole thing may lack stability. What should I do? Tell 'em it needs a back or it might fall apart? Reinforce with gussets? Or just glue the dados and hit it with some brads and clamp the be-jesus out of it? Thx.
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Perhaps he'd go for a back on the top and bottom 8" or so. Even that would give a huge support to keep it from racking. Otherwise, I'd not build it because I don't want to hear complaints later when it shifts to one side and the joints start to break.
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Edwin Pawlowski wrote:

Just wondering - does your friend's wall have a bit of molding where the floor meets the wall? Might not be able to put the cabinet flush with the wall if there is molding there. You might want to nick out a bit of the bottom shelf and sides to allow the cabinet to fit over that molding.
If the cabinet does fit flush to the wall then you might be able to convince him to put in a couple of "L" brackets inside the cabinet that would attach it to the wall. 8' is a heck of a tip no matter which way it goes.
On the other hand, if his ceiling is exactly 8' tall the cabinet may be jammed right in place without worrying if it will tip in any direction.
I was just wondering.
Now, I'll go get coffee.
Josie
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firstjois wrote:

If you do a base with a front piece slightly inset under the first shelf and another cross piece at the top (again slightly inset) it will (in my opinion) look better and have some support to keep it square.
A bigger concern with very tall , narrow cabinets is to give them enough stability from tipping. If the cabinet is not very deep either an oversized base or attach to the wall with L bracket is essential.
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Unless the sides of the shelf are attached to adjacent shelves or something that like that, I'd tell him that it will rack and in short time, lean noticeably to one side. If he absolutely refuses, then tell him you won't fix it when it starts to lean, he'll feud with you after that and you'll both end up as miserable old men with a perpetual grudge match going for the rest of your lives.
Barring all of that, you could go as Ed mentioned or perhaps smaller triangle support pieces on the back of all four corners. Essentially, it's simply not going to look near as good as it would with a full back.
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Alan Smithee wrote:

Another idea is to do a good plinth, about 150 (6")and put some 75 - 100 (3" - 4") rails under the top and and a few of the shelves at the back. With the shelves trenched into the ends a reasonable amount this should give enough support. You can always out a couple fixings through the rails into the wall. regards John
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Alan Smithee wrote:

braces let into the back. Set thwem in flush to the shelves and uprights then use solid wood edgebanding to cover the whole side you put the braces on, or brace both sides and cover both. Joe
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be set against a wall (i.e. not freestanding), if you set in the dadoes 3/8 and square everthing up when you glue-up. you can toe-nail into wall studs from the inside of the shelf to keep it from racking.
If he wants it freestanding, then you need some gussets or something like the others have mentioned.
Lou
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Something this tall ought to have a back.
That said, if you dado deep enough (if it was solid wood I would say to do sliding dovetails) and screw and glue the shelves in, plugging the screw holes, with the thing squared up when you affix the shelves, the assembly will be fairly strong.
This tall and you also need to add earthquake straps of some sort anyway. So that should help prevent any racking.
MikeW

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20 years ago I built a bookcase out of 2x10's with no back (I still have it). It has a very noticeable list to one side. The shelves are dadoed about 3/4" , screwed and glued into the verticals. I wish I had put a back on it. Someday I'll get around to correcting that error. On the plus side, I haven't made that error again.
--
Regards,
Mike
Flower Mound, Texas
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Michael Gresham wrote:

Thank you to everyone who replied. It's given me a lot to think about. I'm feeling more confindent that I can resolve this. Thx.
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