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Diagonal Bookcase design

21K views 19 replies 14 participants last post by  alboston  
#1 ·
I have a project coming up where the client want a bookcase covering an entire wall in her office (14' x 10') and she wants it built diagonally like the ones attached. What would be the most effective method of joinery for where each shelf intersects. Dado, lap joint, maybe even biscuits? Let me know what ya think and if you have had any experience with anything like this..
 

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#11 ·
If I were doing it, I'd setup the router table with a featherboard & dovetail bit for the male ends. Cut them the full width, then remove an inch or so after the fact for the blind joint.

For the females, I'd setup 2 routers, one with a straight bit to plow out most of the material, then do the cleanup with a dovetail bit. Shouldn't be too hard to setup a jig to make these repetitive.
 
#13 ·
You haven't mentioned if you are going to apply a frame to this after box assembly or not.

If you do, it would give you a spot to hide the joints in the box panels. And if you wanted to dado the boxes together they can be through dados. Much easier to do than blind dados. Flushing out the frames can be time consuming though.

If you are edgebanding the plywood, a blind dado would be nice. I would think that your best bet would be a standard dado and with a bit that matches your panel thickness. Nibbling the end of the short partitions accurately is paramount. Another router jig for that may be the easiest to reproduce it. I haven't done it but I think I would make one that registers to the bottom edge of the part and has the proper shape on the bottom that can be copied with a flush trim bit.

All of that work could be trumped with a good method of biscuits or dominoes. The down side to that method is glue squeeze out. That could easily get away from you if you are not careful. If you could just glue the loose tenons without any oozing, go for it.
 
#15 ·
Some notes on dovetail type construction:

-Dovetail is weaker than half dove tail.
-Dovetail joints in plywood have to be relatively loose, since the end grain doesn't slide well. Too sloppy for my liking for this application.
-Make sure you clamp your material flat before making any router passes or your joints will be off as much as the non-flatness of the wood.
-Seal the wood before doing anything, it will keep movement to a minimum and make dealing with squeeze out easier.
-Use one router bit ONLY for all dovetail cuts, and make sure it doesn't make a glue line cut at the bottom of the groove. Two bits may not be exact matches.

When using boards, I only use tapered half dove tails. Blind if I'm feeling lazy about the fit, exposed if I'm going to show them off. Full dovetails have nothing but downsides in comparison.

I never use any kind of dovetail when I'm using plywood, too sloppy of a joint. Only butt (paint grade work) or dado joints (finish grade work).

If I were doing this in plywood with edge banding, I'd put the edge banding on first, sand, seal, cut blind dados. cut shelves, and use a template and router so that I can have the shelf fit in the dados and get the edge band at the front compressed for a tight front fit during assembly.

No matter what you choose, holding tolerances and avoiding cumulative errors is always a good thing. Some methods are more forgiving than others, and joint surface roughness is more important in some than others.
 
#17 ·
as a cabinet maker, when we make wine bottle racks and cubes, we use the "egg crate" joints for the same type of application, all the parts interlock and are removable for cleaning purposes, been doing it this way for 30 years. Works like a charm.
A blind dovetail works but really sucks to clean or refinish each individual cube later.