I built 35 bookcases for my church about 15 years ago. I designed them to get a bookcase out of a single sheet of 3/4" plywood for the frame and another 1/4" for the back. I'd have to dig out the plans to be sure of the dimensions.

The top, middle, and bottom shelf were permanently attached (with biscuits), but other methods would work. Other shelves were adjustable with holes and shelf pins.

The face frame was made of cabinet facing (1x2 and 1x3, if I remember correctly) and was nailed and glued on.

I think making it of 2-by lumber is going to look too heavy and clunky, but that's only my opinion.

The biggest problem with construction grade lumber is that you'll be hard pressed to find anything straight and flat and if you do because of the high moisture content it will want to twist and cup inside of a month.

3/4" plywood would be a good choice but you'll need a way to make straight cuts. You'll also have to cover the edges, although they make iron-on edge banding for that. Plywood probably won't span 3' under a load of books so you'll need to reinforce the shelves. You'll also need a fixed shelf somewhere to keep the sides from bowing out.

Holes and shelf pins are sufficient for the adjustable shelves. A strip of peg board can be used to make a jig to position the holes.

You do need a back to keep the case from racking but 1/4" plywood would suffice.

Do a search on 'sagulator'

Books are actually rather heavy, and plywood with no additional support WILL sag under even a small load.

If you want to save some money use 1x lumber to edge the front and back of the plywood shelves and stiffen them up.

Even pine 1.5 to 2 inches wide is decent on edge for stiffness, with many hardwoods being even stiffer.

With hardwood edging on the shelves you could even get away with 3/8 underlayment plywood.

So just to warn you, I know nothing... but that doesn't stop me from taking on projects and figuring things out. I don't do rabbets or dados either...

Are you attaching these shelves to the wall? If so, you can factor that into your construction plan. You see, normally the backboard, which is important! - is recessed into the back of the shelf unit. You won't be doing that, so whatever plywood you would use would be visible from the outside, plus it'll really just be the nails/screws holding the board on that will be your structural component. Maybe you can do better: Could you just build these shelves onto the wall? You should be attaching anything that tall to the wall anyway.

To do this, you would need perhaps 1x2 lumber, out of which you would make a frame that fits inside your shelving unit box. You then build your box with just screws, as you suggest. Then you attach the 1x2s (or 1x1s) to the wall (on studs), fit the box over the frame, and screw it on from the outside. Then you install your shelves, including the one fixed one to hold the uprights together.

Smart planning would have you size the units so the frames all go onto studs - 16" repeats.

Another thought: metal angle brackets to hold the thing together.

Plus, I'd consider the fir.

KarinL

"metal angle brackets to hold the thing together. "

That would look rather hideous on a bookcase.

More appropriate for storage shelving.

The backing in a bookcase is normally there only to prevent racking of the carcass, not hold up the shelves.

In many cases it is still cheaper to purchase better bookcases and then cut them down than make them from scratch.

The only time making them is usually worth the cost and time is if you need/want solid hardwood bookcases.

The cost of the hardwood alone will swamp the cost of purchased units made of less expensive material.

Brickeyee, it's funny you should pick up on the racking thing, because it brings up something I forgot to mention. Of course the back is only there to prevent racking - that's what I meant when I said structural; it holds the thing upright in effect. But if it's not recessed, then the actual work is being done by the nails, not the board.

Here's what I have observed about bookcases: the back panel is almost always recessed into the back - that helps it do its work. Where the back panel is not recessed, there is almost always a piece of face framing somewhere that plays the same role on the front. So a nice bit of face framing might help stiffen things up considerably, though design-wise, it would be a challenge to make that "go" with 2" thick shelves. Somehow those demand a clean look.

Metal angle brackets come in many forms and permutations, including both utilitarian and decorative. A bit of creative shopping for something to put on the back or inside or outside the case would yield something interesting.

I also disagree with your math, but again, maybe we shop differently. I would think DIY would be the right choice if cost is an issue within the constraints of size and multiples (this was for four units, remember). You might get a fabulous hardwood bookshelf for cheap on craigslist, but 4?), or where the desired size or style is not easy to buy.

KarinL

If you use a lot of smaller nails (about every 3 inches) even a nailed back is more than adequate to prevent racking.

I make a rabbet on the back, but it is not a common thing on purchased stuff until you get to the very expensive stuff.

Have you priced solid hardwood bookcases?

Anything beyond 'printed' wood grain over particles board is painfully expensive, and even decent quality particle board with printed grain is not exactly cheap (often running close to $90 each).

You cannot purchase a decent amount of hardwood of just about any type for the price of a particle board bookcase.

Even is you are wiling to buy lower grade hardwood and glue up every piece more than 3-4 inches wide decent hardwoods are expensive, the cheapest stuff is usually over $3 a board foot.

Thanks for the replies. I'd love some more thoughts on the feasibility of using 2x10 boards (doug fir or redwood) purchased from HD or Lowes for both the shelves and the sides (with 3/4 inch plywood as a back). The look I want is thick (2"). I'm not interested in particle board and I'm not interested in purchasing bookshelves. These bookshelves will be freestanding (no wall behind them), although I hope to be able to anchor them to the ceiling and on one side to a wall (there will be a total of 4 bookcases running all the way across a room, so 2 will have one side that attaches to a wall; 1 of the middle bookcases is going to hinge open to act as a hidden door). With enough screws into the shelves and the backing will I be able to keep the 2x10 construction grade lumber from warping? What's better for this: fir or redwood?

"(with 3/4 inch plywood as a back)"

Even 1/4 inch plywood is more than adequate enough.

If you want eh exposed back to look nice you may have to use whatever you can get decent hardwood veneer plywood.

Doug fir is going to look like hell, and may have significant warping issues.

Framing lumber is not dried to the same level as hardwoods for furniture.

If you purchase DF or other softwoods from a hardwood dealer you may get some dried adequately.

Watergreat said , "The look I want is thick (2")."

2x10s are going to warp and cup and twist - that's what they do.

The EASY way to get that in shelving is to use 1x2 edge banding on standard 1-by-whatever boards. A bonus is that it reinforces the shelf and minimizes sag and warp.

http://ana-white.com/2010/10/ten-dollar-ledges.html Like the edge of these ledge shelves

The Popular Woodworking column, "I Can Do That" article in the June issue (arrived yesterday) has a good article on building basic bookcases "from home center materials with minimal tools". They are a series of boxes of varying depth and height making a modular bookcase. As a result of the stacking the apparent thickness of the shelves is 2 x 3/4" or 1.5" You might look into this as inspiration. If you are feeling really inspired, the next article in the magazine is on reproduction of the reproductions of bookcases at Monticello (the originals got shipped to become the Library of Congress).

Here is a link that might be useful: overview

That column about stacking bookcases can't be downloaded until you register, which I haven't done yet, but I like what the writer says in the synopsis: "We make them that way because that's the way we've always made them."

What's important for furniture users and buyers (and DIYers) to realize is that the way things are "always done" has often evolved for the convenience of woodworkers or to reflect the tools and materials they most often have, for mass production, or for other reasons that sometimes don't matter for a one-off idiosyncratic project like this one, or for the non-woodworking builder who has fewer tools but more flexibility in other directions. In those cases, DIYers are sometimes on their own in terms of design because we have to think outside the box. Below is a link, for example, to a project my husband and I did recently, where our constraints and wishes kind of precluded doing things the way they are "always done" and we had to figure out a whole different way to build drawers.

I'm still not totally clear on some of your project details, for example why you wouldn't be attaching at both ends of the row, whether you can screw into the floor, whether budget is an issue, and what the overall intent of the project is in terms of appearance and function, but there are a couple of alternate ways of thinking about this project. For example, you could look at it more as a wall-framing exercise than as a set of four bookshelves, and take your construction clues from how a wall would be constructed and installed. The stacking boxes that are apparently the idea in the Popular Woodworking articles may also be a good approach. You can construct the stationary and mobile sections differently, and also, your two stationary sets together could be constructed as one unit.

But there is another option if you want to stay with free-standing bookcases that you install and connect. This evolves from the recognition that the back is much more effective if it is inset. Go ahead and use 3/4" plywood, but cut it to fit entirely within the case of your shelves. Lay it on the floor, and then assemble your case around it. Screw the case sides to the top and bottom, as you intend, but then also drill and screw them into the sides of the 3/4 ply all the way around. Now you have a pretty solid box that will not rack, and in which the backing plywood also helps keep the vertical elements in line. An advantage to this is that your plywood edge will not show and in fact, if you use finish-grade plywood, the backs of your shelves will actually look darn good.

Now you can attach your shelves. One of the tricks I use is to shop the moulding section quite carefully (actually I scour a specialty moulding store). Whatever the moulding pieces are designed for, they can be used for other things, for example, keeping corners square or supporting shelves.

The discussion about your lumber selection question also leads me to suggest that you expand your search beyond your big box stores. I shop for the best lumber I can find and often have to go to specialty stores to get it, and I usually pay a premium for it - but since I'm not paying for labour, the total cost of the project still often ends up being very reasonable. Besides getting lumber that is dried in keeping with the sort of work you want to do, you also get a better selection. And I will say that in the square-cut-and-screw method of attachment, a hardwood like maple is going to give you a way better result than a softwood where the fibres on the corners are apt to crush easily when the unit is stressed, resulting in wobbly joints. You may also find that the aesthetic appeal of using really nice lumber is such that you will be happier with better thinner boards than with lesser quality thick boards. Plus, thinner boards give you more room on your shelves.

KarinL

Here is a link that might be useful: home-made drawers

"Go ahead and use 3/4" plywood..."

Way thicker and more expensive than needed.
It is also hard to find in any grade wyou would want showing behind the books.

3/8 overlay is easily available in A/C grade, not that expensive, and more than strong enough for a book case back.

1/4 in Luan under-layment is around $10 a sheet.
Hardwood plywood starts around $30+ a sheet.
3/8 AC underlayment is about $25 a sheet.
HD even has 1/4 inch Birch for $25.

This OP sounds quite capable of making his own decisions and has likely done so by now and is probably well underway making what sounds to be a concealed room for what I do hope is not a nefarious purpose :-)

However, no, it doesn't have to be 3/4 inch to serve the anti-racking role. But as I am recommending screwing into the edges of it, 3/4 will be easier to hit and will allow drilling a touch further from the edge of the case boards. Screws can also be driven into 1/2 inch plywood, especially if the back is recessed a bit into the case, but (a) the OP seems to prefer the idea of 3/4 and (b) if he misses with the drill or his edge splits, it won't be my fault :-)

As for price, I didn't see the OP mention that budget was an issue, although he does show a preference for shopping at HD or Lowes. But this may be about convenience, not cost. As I said above, if you're not paying for labour, and it's one project, you can sometimes afford premium materials.

As for nice 3/4 inch plywood being hard to find, not where I live. At the link below, you can see the variety of both exotic and domestic species plywoods offered at Windsor Plywood stores, and almost all come in 1/8 and 3/4, some also in 1/2. I can attest to it being very nice quality indeed. And usually, anything you can find in Canada you can find more of, more easily, in the US. Windsor does have 4 stores in the US.

KarinL

Here is a link that might be useful: Windsor Plywood

3/4" sides and 1/2" backs are great. You can't find hardwood veneered 3/8" plywood in my area to save your life; it would be a special order with a one-bundle minimum. I was trying to locate mahogany plywood when I found that out.
These were built with 3/4 and 1/2:

Notice Widnsor is a Canadion company.

Shipping to CA is going to be a real PITA for large sheets.

Truck freight territory.

Just because money may not be a driver does not mean you need to waste it on thicker material than required to do the job.

I hope those built in shelves in the pictures above are for nick-knacks.
They are going to sag very badly with books.

Yeah, Brick; could be. They are 1.25" poplar; I can only build the design given me, staying within the budget, etc. If they did sag, they could be turned over as req'd.
Casey