Design Help with Bookcase

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Forum topic by RossCapolupo posted 06-10-2016 04:05 PM 395 views 0 times favorited 4 replies Add to Favorites Watch
View RossCapolupo's profile


10 posts in 296 days

06-10-2016 04:05 PM


Need some feedback on a bookcase I am building. It is a simple, clean 8’ tall bookcase, modeled after an IKEA model that they liked, but was too cheesy. They want it solid wood and painted white, so I went with poplar. They want adjustable shelves, but I convinced them to have a fixed center shelf to support the 8’ side panels.

The carcass is to be 3/4” poplar, joined by half-laps, glued and screwed. The back panel is to be 1/2”, same joinery. For the fixed shelf, ill likely go with a sliding dovetail to give the panels more support.

My issue is that I got 4/4 rough sawn poplar, and the boards are so out of flat, that I think the final panel thicknesses will be 5/8” for the sidewalls. Wanted to know if y’all think that is enough material to have a sturdy product on such long panels? Without all fixed shelves, I am worried about the panels warping along the length. On the plus side, it will be painted and clear coated, so I think moisture exchange will be minimal.



4 replies so far

View JBrow's profile


750 posts in 343 days

#1 posted 06-11-2016 01:57 PM


Some options for the bookcase that avoid the milling problems you are facing are to either make two stacked boxes or make the sides from plywood. With two boxes that stack, the fixed center shelf is derived from the top and bottom of the stacked boxes. The seam on the outside of the case can be covered with moulding to compliment base and crown moulding. Since milling shorter stock is much easier it can keep the bookcase sides at ¾” thick. Alternatively making the sides from plywood avoids these milling problems all together, especially since the project will be painted.

In my opinion, your instincts are spot on; at least one fixed shelf on a bookcase with 8’ sides is a must to keep the sides running true from top to bottom.

Going forward with the plans you laid out, the bookcase would probably be ok if the 8’ sides ended at 5/8” thick. If the sliding dovetail is let in by ¼” rather than 3/8”, the uncut side faces would be 3/8” thick at the dovetail joint as probably planned if the sides are ¾” thick. A shallow rabbet in each side for alignment and then gluing and screwing the fixed shelf in place would be easier. If trim screws are used, wood filler could cover the screw heads.

A bookcase this tall could probably benefit from two fix shelves, especially if the final thickness ends up at 5/8” thick. Books can get pretty heavy, causing the sides to bow. The load on the sides obviously increases with width. If the bookcase is wider than maybe 24”, then a second fixed shelf would help prevent the bowing problem (I could not see the width measurements in your sketch). But if the bookcase is narrow, one fixed shelf is probably enough.

It seems that the real problem is milling the stock to end with 8’ long boards that are flat and close to ¾” final thickness. This is a big challenge with such long stock. My first idea is either return the badly twisted or cupped or bowed stock for better looking rough lumber, or heading back to the lumber yard and selecting a few more but better looking boards from which the sides can be milled.

Whether you return to the lumber yard or not, arriving at ¾” thick x 8’ long finished lumber is not easy. Ripping the best looking long wider stock at the bandsaw to produce narrower stock can require less material removal to get to flat stock when the board is twisted or badly cupped. Lumber that is not twisted or cupped but bowed along its length is probably fine so long as the 8’ board is flat (but with a bow) with parallel faces. The top, bottom and fixed center shelf will probably true up the long bow in the board.

Another milling option to consider is hit and miss jointing and planing until the lumber sets flat. Once the stock sets flat and has parallel sides, the joinery can be cut. The missed areas can then be cleaned up by hand planing, scraping, and/or sanding after joinery is cut but before assembly. Taking your time with careful planning during the milling operations may pleasantly surprise you by yielding stock pretty close to 3/4” thick.

View AlaskaGuy's profile


2398 posts in 1732 days

#2 posted 06-11-2016 08:39 PM

I like some of JBROW’s ideas. Especially using plywood for the sides. Nobody is going to know what under that paint except you and the owners.

I build a lot of tall bookcases with adjustable shelves. Often time I’ll skip the attached center shelf and let the customer figure out the shelf layout. After they do that I’ll add the shelf this type clips to the shelve nearest to the center. These clips with keep the case from spreading.

I can’t ever remember at shelf that comes out exact center of the case.

I screws into the side of the case and the bottom of the shelf.

-- Alaskan's for Global warming!

View bondogaposis's profile


3972 posts in 1774 days

#3 posted 06-12-2016 12:53 AM

I would not use 5/8” stock for the sides, it would look and probably be too flimsy. Instead buy some flat stock. Maybe you can utilize the warped shock for the shelves as as cutting them shorter then removing the warp will result in less stock loss. Bookcases have to be able to support a lot of weight, you will really need a fixed middle shelf.

-- Bondo Gaposis

View RossCapolupo's profile


10 posts in 296 days

#4 posted 06-13-2016 10:49 AM

Thanks to everyone for the great insight!

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