Replies

1. 
   Jimurock | Nov 22, 2009 08:32pm | #1

   Glue the dadoes - the grain should be running in the same direction, so stable enough.  Plywood is more stable than wood, and will be joined to wood grain running in different directions.  Better to brad or staple.  I prefer staples because brads tend to come loose unless put in at an angle.

   Jim

2. 
   SteveSchoene | Nov 22, 2009 08:43pm | #2

   It would be a good idea to be sure that you attach the shelves to the back, nails or screws, since a 4' span is pretty long for books, with just 1x shelf material.  You won't have any cross grain problems with the plywood back and the shelves.  The solid oak will be stiffer than plywood, but without the added stability from face frames could sag if fully loaded.

1. 
   badarse | Nov 23, 2009 12:41am | #3

   THanks for the info.  Would I glue the plywood back to all the shelves and end panels as well as staple or just the fasteners?

1. 
   Jimurock | Nov 23, 2009 03:40am | #5

   Don't glue the back.  The wood will move, the plywood won't.

   Jim

1. 
   SteveSchoene | Nov 23, 2009 04:28am | #7

   The solid wood glued to the plywood back in a bookcase is essentially all long grain to plywood.  Wood moves very little in it's length dimension, not much different than plywood in that regard.  I wouldn't worry about the movement here. 

3. 
   xxxxx | Nov 23, 2009 01:02am | #4

   If you stop the dadoes about 3/4" from the front of the sides, & notch the shelves carefully at the front corners, it'll give the effect of plain butt joints.  It'll be a bit more work, just as strong, & a whole lot neater looking then exposed dadoes.

   Don't forget to make a right & a left side.

   Paul

4. 
   Boogalee | Nov 23, 2009 04:05am | #6

   You may have a problem fitting books on the shelf @ 10".  FWW measures 11"

5. 
   RalphBarker | Nov 23, 2009 06:50am | #8

   Unless the customer insists on it, I'd advise against all of the shelves being fixed. Almost everyone has a few books that are tall.

   Also, assuming a 3/4" finished thickness, 4 feet is a very long span for books. You may need to add a lip to the front, and support the back edge in some way to avoid sag over time.

   As others have indicated, plan on a fair amount of seasonal movement across the grain, but little along the length. Quarter-sawn move less than flat or rift sawn. You need to design for the movement, allowing it all to go to either the front or the back, or in both directions, depending on where you glue. The following link may be helpful:

   http://www.woodbin.com/calcs/shrinkulator.htm

1. 
   DonStephan | Nov 24, 2009 06:27am | #10

   It's past my bedtime, so give me a strong dumb slap if appropriate.

   If the bookcase is solid wood, it seems the grain would run vertically on the two sides, and horizontally on the top, bottom and shelves.  Seems like the case and shelves will expand and contract together?

1. 
   RalphBarker | Nov 24, 2009 07:58pm | #11

   Yes, if all of the grain is at the same angle in all of the boards. It's the variation in expansion/contraction that gets ya. Once you add glue, it's the old irresistible force vs. the immovable object thing. ;-)

   Edited 11/24/2009 11:59 am by RalphBarker

1. 
   DonStephan | Nov 25, 2009 03:26am | #13

   Ralph:

   I think you brought up a subtlety I wouldn't have thought to consider.  Such as a tall blanket chest, no drawers,  Say it's 36" tall, grain direction of the sides and ends horizontal.  Allowing 2/16 to 3/16" expansion/contraction per foot, the chest could vary in height 6/16 to 9/16 over a year.  Make three of the four sides and ends flatwawn, and the fourth quartersawn.  The latter might expand and contract only half what the flatsawn does over a year?  That would make a potential difference of 3/16 to 4/16?  Ah, carumba!  Thanks.

2. 
   DHAM | Nov 25, 2009 01:50am | #12

   I agree with you Ralph. The shelves need a lip on the front by gluing a piece on the front of each shelf about 2 inches wide to help distribute the weight.

6. 
   lwj2 | Nov 24, 2009 01:07am | #9

   You may find this helpful:

   http://www.woodbin.com/calcs/sagulator.htm

   Leon
   
7. 
   Tinkerer3 | Nov 25, 2009 06:41am | #14

   I have built quite a few shelf units like this.  To put it solid full of books, three feet wide is probably a more practical width.  I agree with the poster who suggests stopping the dado before the edge.  A quarter of an inch is enough but be sure they are clamped and glued. 

   Unless the requester for this book shelf has a uniform collection of small books about eight inches high, I think ten inch spacing is entirely too small.  The books in my office are fairly tall but of these books, only about four percent would fit upright in shelves spaced ten inches.  My shelves are spaced thirteen inches and hold all but about three atlases.  Remember, you need space above the books also for handling. 

   You can glue the back on if desired but tacking it closely should do the trick.  It's the back that holds it straight and upright.  The last unit that I built had sides that were bent S shape.  I pulled them straight with clamps to fit the back and the unit now stands perfectly straight.  If you do put a face frame on it, remember to allow for extra height between the shelves.  Go for it.

8. 
   Eef | Nov 26, 2009 12:28am | #15

   bad-a,

   many's the time that a bit of over-spanning can be rectified by gluing 1 1/2 wide wood to the front and back edges of the shelves. one glues the wide face, not the narrow edge, to the shelf edge. of course you'll need to leave the two ends of the shelf "unbanded", as these go into your dados.
   this also allows for the hiding of exposed plywood and you can route a nice decorative detail into the solid wood.
   eef