# How to avoid sag in 5 ft bookcase shelves



## dbldee20 (Jan 6, 2009)

I want to build a one piece bookcase without center support pilars or dividers. I planed on using 3/4"oak plywood with router grooves on sides to hold shelves tight. I wanted to use a 1/2" backing & will screw backing into back of shelves. The shelves will need to be about 16" deep. All shelves will be fixed. 
I thought about cutting the face frame taller than shelves & attach them so they over hang shelves on the bottom. I am considering using angled steel or alum. behind face & under shelf front to add support. The face would hide the metal. Would this be enough to keep them from sagging? Also thought about doubling up on the plywood shelves, making them them 1-1/2" thick. Do they make a dado blade that would cut a groove this thick? I will be using a friends table saw to cut all material.
They would be used to hold mostly stereo components & cd's, no books. 

Thanks for any suggestions.


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## drcollins804 (Jan 11, 2008)

You could also dado the back which would at least give you support all the way across the board from the back side. You wouldn't have to cut it very deep if you do a good glue and screw job across the back.
Hope this helps.
David


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## LarrySch (Dec 31, 2007)

I agree with David - without showing some type of support - the dado in the backside is the best way to go. If three sides are supported - there should be very little sag if any at all. The screws can always be hidden by plugs of the same wood your using.


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## breakfastchef (Jan 14, 2008)

I know this has been posted here before, but it is very applicable to the OP's question. Visit http://www.woodbin.com/calcs/sagulator.htm


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## dbldee20 (Jan 6, 2009)

Thanks for the suggestions. I am now leaning towards adding some pullouts for cd storage, which will require a center wall. 

Thanks.


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