Making Solid Oak Book Shelves

[dwg]

I am going to make 8 solid red oak bookshelves that are 9" wide and 48" long.  I have some boards that are about 9.5 to 10." wide and 100" long.  As far as stability goes, should I just rip the boards to 9" widths and cut to length or should I cut the rip the boards into 3" widths and 4' lengths... mix up the cuts from different boards... and then glue them back together to make the 9x48" shelves.  (I am in Southern California.)
Thanks.
Don

[frigator]

Just use the wide boards.

[Joel H.]

Agree with frigator. Nothing to gain by ripping to 3" - unless there is a slight bow lengthwise to the boards. Then your questioned method would probably straighten the bow. It would have to be a slight bow though.

[WaterlooMarc]

Solid boards.

[Papa Jim]

Solid!

[Bibliophile 13]

Just use the wide boards. I don't know who first popularized the idea that wide boards should be ripped and re-glued, but with properly seasoned lumber, there's no need. Especially with casework, where the joinery of the case itself will help prevent a lot of warping, there's absolutely no point in ripping them down and re-gluing them into panels.

[Routerman]

I doubt they're flat and straight at 9" + wide.
I've never seen a flat board (un-milled) that wide.
And if your sticks were not stickered, they are misshapen.
If you have the thickness, I'd rip, joint, & plane them and glue them back in order.
If they are all flat and of equal thickness I'd leave them alone.

[ruffcutt]

I doubt they're flat and straight at 9" + wide.
I've never seen a flat board (un-milled) that wide.
And if your sticks were not stickered, they are misshapen.
If you have the thickness, I'd rip, joint, & plane them and glue them back in order.
If they are all flat and of equal thickness I'd leave them alone.

How many solid wood book cases have you build?

Do you recommend the same process for plywood book cases, my plywood is never perfectly flat?

[Routerman]

Have flattened (milled) a lot of lumber.
The carcasses need the joinery, not necessarily the shelving.
But inevitably, shelves need to be flat and of equal thickness.
Connections and shelf hardware accommodations are easier with flat
equal thickness panels.
Plywood is always problematic. Thin, un-flatten-able, bends under load, always
requiring some edge banding, not easy to join. I rarely use it for shelves.

[PaulJohnstone]

48" long is kind of pushing it for bookshelves, especially if they are adjustable shelves.
A lot of weight for that big of a span.
You will likely need some kind of support in the middle (dividing it into two 24" sections).
There are other ways of reinforcing it too.
I would recommend redoing the design so instead of 8 shelves at 48" span, instead do 10 shelves at about 32" span  if possible.
If you already know this and have accounted for this, I apologize.

Also, I am a big fan of fixed shelves, with the back nailed to the back of the shelves for increased rigidity.