How about an inch wide strip of 3/4 ply supporting the shelves lengthwise
both at the front and at the back of the shelf?
Would this help?
Vlad



"Bob Gramza" wrote in message
om...
http://www.woodbin.com/calcs/sagulator.htm


"Vlad" wrote in message
ble.rogers.com...
: Hi all,
:
: I am planning a couple of bookshelves to be made from a 1/2 inch
plywood,
: 35x11 inches in size; some shelves will be fixed in 1/4 inch deep dadoes
in
: the sides of the bookcase and others will be "floating", supported by
pins
: inserted in 1/2 inch deep holes. The shelves will only be supported on
the
: sides; not along the length. Should I worry about the sag of the
plywood?
: What's a good length of the shelf that can sustain a load full of books
: without additional lengthwise support?
: Thanks!
: Vlad
:
: