Woodworking Talk banner

1 - 17 of 17 Posts

·
Jeff G
Joined
·
189 Posts
Discussion Starter #1
Hi everyone,

I'm getting ready to build a simple bookcase, but I'd like to do it without putting a back on the case. The plan is a low book shelf that measures 35" tall x 36" wide x 12" deep. It will have three fixed shelves. I plan on using 3/4 ply for everything and then putting a hardwood face frame on. My question is, will this be stable? As in, without a back, will it rock back and forth? If yes, would a diagonal hardwood brace in the back fix the problem?

Thanks a lot!
 

·
Jeff G
Joined
·
189 Posts
Discussion Starter #2
And here's a quick sketchup of what I was thinking.

...and one other option is to add vertical supports in the middle of each shelf. This would help with sag as well.
 

Attachments

·
Sawdust Creator
Joined
·
8,047 Posts
The design you have there would have little resistance to racking, or essentially folding down to the side. You'd be putting a lot of stress on those few bottom joints. Here's where a back panel would eliminate that...a diagonal brace would help...but in my opinion not the best choice aesthetically
 

·
John
Joined
·
3,028 Posts
Hi Jeff - with the shelves dado'd in and glued, plus a good solid face frame it should be fairly stable. If you want to beef it up some more, add 1x2's across behind the shelves with the shelves dado'd into those also. You would want those with the 2" dimension vertically and also attached to the sides. Those would also help stiffen the shelves. :smile:
 

·
Registered
Joined
·
12,595 Posts
Dados, glue and face frame with a good glue job should hold up well. Unless some kids want to swing on it.

George
 

·
Jeff G
Joined
·
189 Posts
Discussion Starter #7
cabinetman said:
Is the cabinet to be free standing on the floor, or on the floor and screwed to the wall, or wall hung off the floor?





.
Free standing. Not braced to a wall
 

·
where's my table saw?
Joined
·
27,866 Posts
I get the look

But you're askin' for trouble with out some sort of enclosed area at the back... if there is a back side?

One solution is to alternate panels on ont he front another on the back an so forth.

Another solution is to use a clear panel for one aside.

A diagonal brace or an "X" brace would help to make it more rigid.

Another is to dado the verticals and then add full size blocks between the shelves/dados to essentially make deeper dados by filling in between them.

If you don't brace it in some manner the first time somone pushes against it it may just collapse. Rectangles are only as strong as the joints that connect them. A triangle is a much stronger element and the joints can be minimum. Make a square and use a rubber bands to secure the corners. Then make a triangle and you'll see what I mean. You can't fold the triangle, but the square will collapse easily. A back that's rabbetted in or nailed on will have the same effect as a triangle brace.
 

·
where's my table saw?
Joined
·
27,866 Posts
in a perfect world, yes

and keep in mind.....a full shelf load of books can be pretty heavy...
And it is also static, not dynamic.

George
As far as things around the home goes, books are among the heaviest common objects. Records are also right up there. :yes:

In the real world "things" happen. Things like children may push or climb on it, an adult may lean on it accidentally to gain their balance or even on purpose to rest. When this happens, that mass is put into motion creating momentum, a dynamic condition, which the joints have to resist. They may resist it to a point ... then fail, if they are weak OR if the force against them is too great. It may never happen, but just in case, a back or suitable bracing will prevent it.
 
  • Like
Reactions: BWSmith

·
Banned
Joined
·
3,535 Posts
At 36" wide, you're going to have some sagging without /something/ for support of those shelves. A face frame will help prevent the racking, somewhat, but you're better off adding a back as well. Or you can build it as a modular set of "boxes" that stack and then reinforce each other to prevent racking. That entails a completely different style of build and design, though, and won't look like what you seem to be going for with this design.

Unless you're going to secure this thing to a wall, it's going to collapse at some point. Someone will lean on it wrong and the whole thing will just slide sideways given your current design.
 

·
where's my table saw?
Joined
·
27,866 Posts
frank's idea of modular boxes sounds good

That way each box will have more structural integrity. You may also eliminate the need for dados and could just use rabbets. Capping the edges of the shelves will add strength and keep them tied together in a unit. :thumbsup: I like it!
 

·
Registered
Joined
·
291 Posts
I built some like that as well as some angled shelf magazine racks. I used sliding DTs, but it's not necessary. Dados and a face-frame front AND back. A 3 inch base gets it off the floor and keeps toe kicks below the books!
If I were to do them today, I'd glue and pocket hole the face-frames.
 

·
Registered
Joined
·
2,319 Posts
My approach would be to make the shelves with a slight dado in the uprights, but 3/4" ( or whatever stock you choose) X 1&1/2" glued to the front of the shelves and extend beyond the shelves into a blind dado (say 1/2") in the uprights. These of course will be covered by the face frame. Do the same for the back of the shelf. The shelf itself would in the case of 3/4 X 1+" stock be 1&1/2" narrower than the uprights, and the 3/4X will stiffen not only the shelves but aid in preventing racking.

Icing on the cake would be 3"X3" triangles (fancy scroll sawed profile) glued in each shelf corner at the back.
 
1 - 17 of 17 Posts
Top