Hi,
My brother-in-law wants me to build him a couple of bookcases for his home office. We haven’t decided on the building material yet. Leaning towards 3/4″ eastern pine. I’d prefer to build them out of 1″ material but I’m not sure if Home Depot sells 1″ pine/poplar. Hardwood is definitely out of the equation. The bookcases are only being used to store binders a few art books and hardcover books. He wants them to look good but most importantly they have to be able to support approx. 50lb per shelf. (that’s just an estimate)
This much we have decided on…. width 28″ height 72″ (6′) depth of shelf 11″ since the widest piece of pine is 1X12 which is actually (3/4″ X 11 1/4″) I’ll be using pine panel board for the back instead of 1/4″ pine plywood. I’ll cut a 1/4″ dado in the backs of the sides to house the 1/4″ back. The top shelf and bottom shelf will be dadoed to the sides. That should give the bookcase some degree of strength/support. The shelves in between will be adjustable. I will be using adjustable metal standards. Providing I can find them.
I’m thinking he’d probably be better off with fixed shevling (dadoes housing the shelves) for max. strength since that is a major concern. But if the 3/4″ pine can support approx. 50lbs of books per shelf then I’ll go ahead and build the bookcases with adj. shelving. That way he’s free to adjust the shelves to any dimensions.
Wanda
Replies
Wanda,
I think expecting even a full 1" thick shelf to support 50 lb of books without flexing is asking too much. Right now, on either side of my desk, are 2 built in bookcases slightly wider than the one you propose (mine are 34" W). The shelves are 3/4" red oak plywood with 1" wide attached ledger strips at the front. My books are not even close to 50 lb pershelf, but my shelves are still bowing about 1/4" in the middle, each. I would recommend, if you use the Home Depot 3/4" thick pine or poplar, use at least 1 1/2" wide ledgers glued to the front of each shelf to prevent bowing. Also, using shelf standards or pins for adjustability sounds OK, but I would make the middle shelf dadoed into the sides, to prevent the sides from flexing out. Good luck with your project. Gary
One way you can cheat with these things is to add a front strip to the shelf, maybe like an inch, with the wood grain turned in a quartersawn orientation. Really strengthens the shelf.
By itself, the pine shelf would sag about 1/32" under the load, which is well within the acceptable range of a 32nd per foot. If you rigidly attached a 1.5" trim piece to the front of the shelf--that is, the trim makes the shelf look as if it were 1.5" thick--the total sag on the shelf is decreased to about 1/64". Adjustable shelves would work just fine, in other words. Even allowing for shelf 'creep' under continuous load over time, the sag, especially with the trim strip, is in the acceptable-to-most-people range.
http://www.woodbin.com/calcs/sagulator.htm
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