advice on building bookshelves

[Bob Venable]

I need to design and install a large set of bookshelves in my home.
I am planning to build them out of 3/4 oak ply with the cases each being 3' wide x 8' tall.
I plan to place 5 permanently installed shelves in each case in addition to the top and bottom pieces.

I will need 8 of these units. They will be secured to the studs in the wall as well as to each other.
Also, I am going to use a piece of 1x2 oak splined to the front edge of each shelf to
improve the stiffnesss and reduce sag....I have a lot of HEAVY books.

My question is what is the best way to install these shelves in the cases?
I can use biscuits, or I could rout dados in the sides and back of the cases. Or ???

I was thinking that the dados would be the strongest, but it might be tough to get
the dados aligned perfectly on the back and sides.
What do you guys think?

Thanks in advance for any help!

[Jamie Buxton]

You can use either biscuits or dados on the ends of the shelves, but really what will hold things together is the butt-glue joint at the ends of the shelves. I'd glue up the sides, top, bottom, and the shelves, and than staple the back plywood on. I'd staple the back to the shelves too -- no need for a dado there.

If the bookshelf side is visible, rabbet the side to conceal the edge of the back plywood.

[Bill ThompsonNM]

Dados would be best on the ends and shouldn't be too difficult to get aligned. I'd be more likely to use screws or dowels through a relatively thin back for the back edge of the shelves. Watch out you don't get them so long they sag!

[Carl Beckett]

I would just screw right through the sides into the shelves (with glue). Would use the backing with staples (and recess this in a rabbet where exposed, so the outside panel might be slightly deeper than all the rest to cover this backing edge)

Where/if a side is exposed you could dado so no screws showing from the outside. Alignment not an issue because only need to dado one side of the shelf (the opposite side is screwed)

I have a few utility bookshelves where I have added an edge with glue and a brad nailer. Same for the top and bottom trim pieces. Fast, and has has hld up well for.... 8 years now

Sounds crude, but will perform well and look good.

[Sam Murdoch]

Using a rabbet and dado joint rather than a fully housed dado for the shelves will give you the strongest joint. Here is a link with a few illustrations - see page 149 of the book http://books.google.com/books?id=dmClj9dTOZQC&pg=PA147&lpg=PA146&ots=1lMOk-BEYu&dq=tongue+dado+shelf&output=html_text

With this joint and a sold wood front edge you don't need to dado the back. I would use at the least a 1/2" back and then screw the backs into the shelves. The 36" width of a plywood shelf will be maxed out for sag but you'll be fine at 36" or less using this construction. If you decide to go wider it would be a good idea to add a cleat at the back under the shelves.

I see this is your 1st post in nearly 2 years as a member. Jumping in with both feet now though. :) Good luck - have fun.

[Tom Clark FL]

Bob, You are describing the bookcase i built about 25 years ago, early in my woodworking hobby. It used to hold magazine collections until we moved across the country. I used face frames of solid oak. Under both ends of the fixed shelves is a piece of plywood 3/4 thick, 1.25 wide, and 12" long. It was nailed with my finish nailer to the sides, and the shelves nailed to it. These supports, along with the face frames make for a very strong shelf. The back is just 1/4" ply, but it keeps the unit from racking. Just some simple ideas on how to build a very strong unit.

[Jim Matthews]

Make certain your router bit is sized to the plywood used for the shelves.

They may be listed as a nominal 3/4" but actually under that size.
Whiteside sells a bit set that will match most plywood thicknesses.

If you're doing more than one bookshelf, a jig will be a worthy time investment.
http://www.woodworkersjournal.com/Main/Articles/Skill_Builder_Dado_Joinery_on_the_Router_8872.aspx

[Sam Murdoch]

Make certain your router bit is sized to the plywood used for the shelves.

They may be listed as a nominal 3/4" but actually under that size.
Whiteside sells a bit set that will match most plywood thicknesses.



This is an added excellent reason to use the rabbet/dado joint. Dado the sides with a 3/8" or 1/2" router bit of your choice then rabbet the 3/4" ply to fit. The plywood thickness is never an issue and then the shoulder of the joint adds a great deal of stability and resistance to racking plus added glue surface. Much stronger but admittedly more work. Worth it though IMHO.

[Prashun Patel]

I'd make an adjustable dado jig and use a 3/8" spiral bit to cut the dados. I would use 1/4" on the back just to prevent racking. I'd only dado the sides. To improve strength of the 36" shelf span, I'd make a 1 1/2" edge band on the front end.

[Carl Beckett]

. Under both ends of the fixed shelves is a piece of plywood 3/4 thick, 1.25 wide, and 12" long. It was nailed with my finish nailer to the sides, and the shelves nailed to it.

.

Even more simple. And very strong.

[Harry Hagan]

A friend asked me to finish the library in her new home several years ago and I was given strict orders that she didn’t want sagging shelves “like in the old house”. She also wanted permanent shelves which made solving that problem easy.

I dadoed the back as you suggested. Alignment won’t be a problem if you cut the sides and back at the same time and maintain that alignment when routing the other dados in that unit.

[John Lanciani]

One thing to consider with this project is materials usage. If you're not 100% commited to the 3' width you may want to consider moving down to 32" instead. That way you can get 12 shelves out of one sheet of plywood (assuming 12" nominal depth) with basically no waste. If you go with 36" width you only get 8 shelves and you end up with a 2'x4' scrap of ply with the grain going the wrong way. Going further, 24" widths give you the best usage of whatever ply that you're using for the backs as well.

[Michael W. Clark]

One thing to consider with this project is materials usage. If you're not 100% commited to the 3' width you may want to consider moving down to 32" instead. That way you can get 12 shelves out of one sheet of plywood (assuming 12" nominal depth) with basically no waste. If you go with 36" width you only get 8 shelves and you end up with a 2'x4' scrap of ply with the grain going the wrong way. Going further, 24" widths give you the best usage of whatever ply that you're using for the backs as well.

Excellent point and the proportions may be a little more appealing too. Make a scaled sketch and play with the FF and shelf edging widths. The widths you have called out are probably sufficient for strength, but a wider width may be more visually appealing? These bookcases are going to be large and a focal point. I think Norm did some large bookshelves (Greek or colonial bookcase?) that used wider FF and looked really good. It may give you some ideas or confirmation on your design.

Make sure you have a way to get them to the space or assemble them in place. I have some 6'Tx3'W shop cabinets that are a real pain to move because of their size and weight. They have similar construction as you have described, but I have two movable shelves with heavy tools. The middle shelf is fixed. Case is 3/4"ply with 1-1/4" red oak FF glued and nailed on, shelves are 3/4" ply with 1-1/4" T x 3/4" Thk red oak eadging front and back, the back is 1/2" ply. The fixed shelf is a fully housed dado glued and bradded at an angle from the inside. The movable shelves are on 1/4" brass shelf pins (the shelf pin holes are probably the weak link). No problems in 7 years including a move.

Mike