Advice needed on bookcase . . .

[Geoff Barry]

A few months ago, it a moment of inspiration, I got a reconditioned DW735 planer and 25 bf of splintery, splintery lyptus. However, as time passed, I realized that I would need 30 bf for what I wanted to build, and as I have to keep everything outside, I was starting to lose a fair amount of usable wood to splitting. So, this past weekend, I threw together a simple bookcase. (I have to work outside, I work a lot of hours, and I have 3yr old triplets, so the story of my woodworking life is that I get a good start on something, then it sits outside for months while weather, a large dog, and kiddies take their toll . . .)

Below you can see the bookcase (and the large, helpful dog) - so here;s the problem: I made what should have ben a small arts & crafts book rack as large as I could with the wood I had. As I was removing the clamps, it occurred to me that a bookcase this size (48" sides, 4 3ft shelves in 3/8" stopped dadoes) should have had a back or a face frame to dgive it lateral stability. Given the stopped dadoes and the rounded sides, neither is feasible now.

I do, however, have a number of leftover lyptus shorts, and I have no yet oiled or sealed the wood. I could put some sort of blocking under the shelves (or some of the shelves). Any ideas short of nailing a 2x4 diagonally across the back?

[Mark Singer]

A back reaaly helps. Diagnol braces , if continuous would also help.. A couple of full width deep drop down edges on the self fronts or backs securly attached to the sides would also help.

[Don Baer]

You mention that you have some shorts hpw lon gare they. I think you might get by puttiinf some 3/4 or 1 bye's (whatever the thickenss of the shelves) across the lower shelves on the back to provide some anti-racking. Thort of that take a piece if thin veneer and make a back that will cover the back of the case. You can use door skin for this.

[Don Baer]

I see that my good friend Mark and I agree on the back.

[Mike Cutler]

Geoff.

I agree, the back is the place to "shore it up".

It's a nice case, but you have created a reflex parallelogram, Think rear derailleur on a bicycle. All of the structural members are equal, and therefore can move at the same rate. To fix the problem you have to inhibit the ability of the pieces to move together.

I like Marks idea about the drop down edges. You might want to consider making them in an Arc, ala Limbert, and have them meet the vertical and horizontal surfaces at each corner of the shelves. left, and right. Replicate the arch with some portion of the radius of the top of the vertical ends

TRIPLETS !!!!! Didn't anyone school you on Plancks Theory of Universal Chaos. When the number of munchkins divided by the number of adults is greater than 1, Chaos reigns.:D :D ;) That has to get pretty interesting at times.

[Geoff Barry]

Chaos would be a good description . . . :D

Yeah, I don't know what I was thinking making a bookcase sans back - I usually have both a face frame and a back . . .

My shorts aren't long enough to span the back, and putting a back on is complicated by several factors: The edges of the sides are rounded, so routing out a rabbet for a back would be tricky (for me, anyway). Even if I got a back on, the shelves stop 1/2" before the back, so it would create odd gaps unless I used 1/2" plywood for the back. But, if necessary, a kludged-on back it will have to be. I could run an upright 1x3 or 1x4 piece of 3/4" oak or something at the back of the top shelf to hide the top edge of the plywood.

Here are two other options, though:

1. Take triangular sections of my shorts, and cut a concave curve into the long edge, then glue these blocks into the corners under the shelves at the back of the bookcase. That would add a little stiffness, anyway.

2. Get some sort of secondary wood (read: can pick it up at the Borg s4s), poplar, oak, or maple would be my options (which goes best w/lyptus?), and run a 1x4 with a mild arch under each shel at the back. Still not as good as nailing a brace of some sort to the back, but more rigid than option No. 1.

Any sense to those options, or am I just fooling myself because I don't want to tack a piece of plywood to my lyptus bookcase?

[Attached is a photo of my last bookcase showing that I once understood the need for backs and face frames -borg white pine and poplar. Ironically, I had fairly straight pine, and made a short case to see how it would come out. When I went back to get more to make a four-shelf version, I couldn't find any straight boards, hence the move toward rough lumber . . .]

[Art Mulder]

Have you got, or can you borrow, a pocket hole jig? My first thought would be to glue a board (like a 1x2 or 1x3) along the bottom of the back of each shelf, and then use a hidden pocket hole (from behind) to fasten it to the sides. I think that would add a fair bit of stiffness.

Unfortunately, you mention that your shorts aren't long enough. How close to long enough are they? I think it was fine ww that showed a trick to "lengthen" a board recently, if a board is almost long enough. You cut a sharp angle, apply glue, and you can slide the joint so the board gets longer -- and narrower too, of course. I think this is much like a scarf-joint (?) in timber framing

Yes, a full back would be best, but even some side-to-side bracing would help. I have attached a picture (old and poor, sorry) of an open-backed bookcase I made 9 years ago. On that bookcase, there is a back across the section with drawers, and a smal 1x1.5" brace under the back of the bottom shelf. Not much, but enough to stop the racking.

Another idea... what if you found a 1/4" piece of plywood, and painted it to match the wall where you are placing the bookcase? It'd be a bit of an optical illusion, as it would appear to be the wall behind the bookcase.

The final idea is to try those corner blocks that you mention -- but again, you may want some pocket-hole screws, or similar, for the end-grain portions of the blocks. And if those corner blocks don't cut the mustard, then use them to screw the shelf to the wall.

hope some of these ideas help.