I (Ben Bradley) have made several of these for my personal use. My early bookcases were three feet wide, but moving was a process of putting books into boxes, moving the shelving and the boxes, and putting the books back on the shelves. It was unknown whether the bookcase would hold together if tilted while fully loaded, because it was too heavy to pick up when fully loaded
This one was assembled at Freeside after the November 5 Open House and is based on my current design, as follows:
Components used (available at any Home Depot or Lowes):
(4) 1" x 8" x 6 ft pine board (actual measurements 3/4" x 7 1/4")
(1) 4 ft by 8 ft. x 1/4" plywood board.
(48) 2" long wood or drywall screws, coarse thread preferred (about half of a 1 lb box)
(30) 1" long wood or drywall screws, coarse thread preferred (about a tenth of a 1 lb box)
Chop saw, table or circular saw, hand sander, electric drill/electric screwdriver (two preferred, one for drilling and one for screwing), 1/8" or 5/32" drillbit, clamp that opens to 19"
Compare the lengths of the 6-foot boards. They can differ by 1/4 inch or more. Choose the two longest for the sides. If their lengths are different, cut the longer one to match the shorter one.
Cut the two remaining ones into eight equal-length pieces. The length of 17 3/4 works well as it gives enough space for the saw kerf and a little extra for variations in length.
Sand one side of each of these (this will be the top side where books rest on it), and on one long edge, sand a "curve" along the edge so it is rounded off. Alternately, use a roundover bit in a router to round this edge.
Put the side edge of the first or "bottom" shelf piece against the side of one of the side pieces at one end. A clamp may help here. The rounded edge should NOT be next to the bottom of the side.
The diameter of the hole drilled for screws depends on the screw size used. Older projects used #6 drywall screws, where a 1/8" drill bit work well, but the Home Depot used for parts for this project only had #6 (slightly larger) screws, and a 5/32" bit was used successfully.
Drill a hole about one inch from the front or back edge so that it goes through the side and into the shelf piece equidistant from the top and bottom (for a 3/4" shelf this will be 3/8" from the edge, but I always eyeball it as the center - it's good enough), and into the wood about as far as the screw will go, or perhaps 1/4" less than the screw (set the drikk into the chuck to extend this distance). Be sure to drill straight, so the hole is parallel to the shelf and the screw won't come through.
Screw the screw in, using a drywall screw setter bit. This is a Phillips bit with a metal ring around it that will cause the bit to slip out of the screw once it is just below flush with the wood. This gives excellent strength and prevents accidentally screwing the screw too far into the side, which is easily done with an electric drill/screwdriver.
Drill a second hole the same one inch distance from the other side and put a screw in it. Drill a third hole midway between the other two and put a screw in it. I do it in this order as it's easier to eyeball the middle of the board near the edge, and then it's easier to make the hole in the middle midway between the other two that are already drilled.
Drill the other side of the shelf to the other side piece as above, so that the two side pieces are parallel.
Make two "spacer" pieces of wood using scrap (such as a length of 1" x 8" or smaller), exactly 9 3/4" long. This will be the distance between shelves, and determines the height of the books that will fit between the shelves. Be sure the top and bottom edges of these pieces are parallel, as this is needed for the shelves to all be horizontal.
Put the two spacer pieces along the side pieces and touching the bottom shelf, and place a second shelf between the sides so it touches the other ends of the spacers. This gives a precision height to the shelf without measuring. Make sure the rounded over edge of the shelf is on the same side as the rounded over edge of the bottom shelf. Drill holes and use screws to attach this shelf. Pull out the spacer pieces. They may be moderately tight, but can usually be removed by hand.
Continue attaching shelves in this way until you get to the top shelf. Align the top of the top shelf with the tops of the side pieces, and drill and screw it.
Cut the 4' x 8' by 1/4" plywood to the dimensions of the back of the bookcase, which should be about 19 1/4" x 6 feet. Align it with the back (the side opposite the rounded over shelf edges), and attach it using 1" screws spaced about every six inches.
This bookcase is for Octavo sized books, and the top shelf is just large enough for mass-market paperback books. I've made a similar shelf that fits (almost?) all Quarto sized books and magazines with 1" x 10" boards cut about 14" wide (five shelves per 6-foot plank, seven shelves per bookcase) and with 11 3/4" spacing between the shelves.
These bookcases may weigh 200 lbs fully loaded, but can be moved by one person with a handtruck. Push on the side until the bottom lifts up, put down on the handtruck, then pull back with one foot on the handtruck axle, and move while balanced as shown in the photograph. It can lay down in a pickup truck bed, or stand up in a tall enclosed truck with it tied to the walls.