Bookcase Joinery Advice?


Dubya

Recommended Posts

It's my first time on the forum, though I've been watching Wood Whisperer videos for a while (thus how I knew to come here). Hi everyone!

I'm pretty new to this in practice, but I'm the type who studies up for a very long time before taking the plunge. That of course means that I'm not at all an expert, but I have lots of ideas for ways to get in trouble...which is why I'm coming here for some advice :)

I'm turning a room in our house into a library, with shelves inspired by Frank Howarth. Before starting on the built-ins though, I plan to make one or two freestanding units, using a similar design. I'll add a strip to the faces to hide the layers, just like in the video. I've attached a picture of a quick Sketchup mockup of the box, without one side (for clarity), the center verticals, or the base. Oh and I'm not sure on the finish yet, so I'd like to keep my options open

There are two problems I've encountered in the planning phase, one stemming from the other. Frank's shelves didn't really have to account for plywood layers at the ends, but a freestanding set does...and I haven't convinced my wife to like the look of 13 layers of birch (though I think it's pretty cool). That means that a rabbeted end matching the dado in the middle, showing off the layers at the very end, is out. I don't want to edge-band such a small spot (it'll either hang over, or I have to precisely account for it while cutting the rabbet). I feel like I'm stuck going with miters...so my first question is, is there any better option?

My second issue comes from the thought of the miters: strength. If I glue the center panel into the dados, it'll massively increase the strength. However, given that it's a large panel, I'm hesitant to do it. I know plywood is more stable than solid wood, but that's part of what I just don't know! I'm also not sure about gluing in the middle vertical supports. Alternatively, I considered a spline like this, perhaps with a metal flatbar instead of wood (because it might be easier than cutting the thin strip for the spline)

Any thoughts would be appreciated, thanks!

Bookshelf.jpg

Link to comment
Share on other sites

Welcome to the forums!

If your cabinet is floor to ceiling then, those little bits of ply your referenced wouldn't be seen.  If, you're going to see the top, the easiest way is to attach a solid top over the ply top.  You can let it overhang a bit and give a nice visual to the piece.

As for gluing the ply, that's what I'd do on this piece.  Ply is much more stable so, you don't have to worry about wood movement like you do with solid.  On that note, if you attach a solid top over the ply, simply oversize a the screw holes in the ply only when you attach the top.  This should allow for ample wood movement. 

Link to comment
Share on other sites

25 minutes ago, TIODS said:

Welcome to the forums!

If your cabinet is floor to ceiling then, those little bits of ply your referenced wouldn't be seen.  If, you're going to see the top, the easiest way is to attach a solid top over the ply top.  You can let it overhang a bit and give a nice visual to the piece.

As for gluing the ply, that's what I'd do on this piece.  Ply is much more stable so, you don't have to worry about wood movement like you do with solid.  On that note, if you attach a solid top over the ply, simply oversize a the screw holes in the ply only when you attach the top.  This should allow for ample wood movement. 

I forgot to mention...this one will be 3-4 feet tall, in the middle of the room (hence the need for it to be freestanding), and be accessible from both sides (hence the "back" panel, which isn't in Howarth's original design). I re-read that post so many times before submitting, I can't believe I forgot to mention that! Sounds like I just might do the gluing after all (and to clear up what I meant: everything you see here is plywood)

10 minutes ago, Aj3 said:

I'm trying to figure out where the miter go.

Keep it simple new woodworker always over think things and over build.

Even butt joints with nails thru the sides and solid wood edges on the plywood would be better than most stuff you can buy from Stores like  Living spaces or IKEA.

Aj

The diagram doesn't show where them miters would go (partly because I'm not good enough with Sketchup yet), but if you take out that center panel and add the closest one (which is missing because it would block everything else from view, making for a pretty horrid diagram), those four corners would be mitered. To put it another, possibly clearer way, all of those short lengths!

Maybe I shouldn't be so picky, but I'm going to try to avoid nails or any other visible fasteners. I know it'll be slow going, but I'm okay with that

Thanks for the quick replies, and the welcome!

Link to comment
Share on other sites

An additional top would still hide those sections you're talking about and you wouldn't have to do the mitered corners.  

If you don't want that notch in the edge banding, a stopped dado would work there an a notched divider to account for the stopped dado.

Link to comment
Share on other sites

Since you mentioned your just starting out.Im thinking just cutting square pieces are going to be a challenge.Adding miters to the corners is even harder.

Are you going to use prefinished plywood.

You don't mention what tools you have.

I can make a nail hole very hard to see in most materials.But I haven't needed to do that since I bought a Domino.Hint Hint 

                                                           :rolleyes:

Aj

Link to comment
Share on other sites

10 hours ago, Aj3 said:

Since you mentioned your just starting out.Im thinking just cutting square pieces are going to be a challenge.Adding miters to the corners is even harder.

Are you going to use prefinished plywood.

You don't mention what tools you have.

I can make a nail hole very hard to see in most materials.But I haven't needed to do that since I bought a Domino.Hint Hint 

                                                           :rolleyes:

Aj

LOL yeah...no Domino, nor any means of purchasing one yet!

I'm not a complete raw beginner, but my experience is mostly hand tools as a kid and a little bit of power. My dad and grandpa were hobbyist woodworkers, which has sort of given me some of the push. I have more experience with little stuff; plywood is sort of a new beast for me. However, I did a project (secret door inspired by Bob Clagett) with it his summer, and want to [carefully] branch out. This bookcase will probably *not* be my first project, I'm just planning way ahead!

As for tools, I plan to buy a job site table saw this winter (hoping for a good Black Friday deal or something), but otherwise it's all handheld power: circular saw (for which I do have good guides, and actually plan to jig one up to be reliably repeatable), drills, impact

I was thinking unfinished, to leave my options open

TIDOS: thanks for the thoughts, I'll consider them!

Link to comment
Share on other sites

Ok new question that came from a conversation with my wife: if I do go with a basic rabbet joint there, how would the strength of the box be affected if I added a 1/4" strip of something (like the maple on the face of the original design) to the end of the plywood, to hide the layers?

I'd shied away from that idea, worried about strength in general, but if I'm gluing the center panel in anyway, that wouldn't be as big of a deal. I'd also do this same cover-up on the end of the wall-mounted bookcases (more-or-less just like the video in the original post, though because I'm not traveling with them I think I'll forgo the "I" design and just do a long dadoed plank for the top and bottom)

If my question is unclear, let me know...I'll do a quick sketch to explain

Link to comment
Share on other sites

16 minutes ago, TIODS said:

I really don't see any additional strength out of facing the ply with a thin strip of maple.  If you're talking about shelving within the cabinet, here's a calculator that will help you determine sag.

I was probably unclear...though I do appreciate that calculator! The 1/4" strip on the face of everything is purely cosmetic, covering up the layers of the plywood. Any strength added is just a bonus

The question I just posed was meant to ask about negative effects of doing the same cover-up, but on the short ends. I've attached a picture to help clarify. The face strips are not in place, so you can see only the plywood and the strip in question, which I've colored lighter for clarity

Screenshot 2016-10-23 at 9.48.32 PM.jpg

Edited by Dubya
reworded for clarity
Link to comment
Share on other sites

I want to say Marc talked about dado/rabbet depth on Wood Talk Show some time. Marc and Shannon made it seem that as long as there was sufficient purchase for the shelf/top going deeper weakened more then it strengthened. I want to say their suggestion was 1/8" to 1/4". 1/8" seems a bit shallow to me.

14650467_10101144444466249_3622615207453

Link to comment
Share on other sites

46 minutes ago, Chestnut said:

I want to say Marc talked about dado/rabbet depth on Wood Talk Show some time. Marc and Shannon made it seem that as long as there was sufficient purchase for the shelf/top going deeper weakened more then it strengthened. I want to say their suggestion was 1/8" to 1/4". 1/8" seems a bit shallow to me.

I'll have to look that up. I saw this article, which recommended 1/4", so I planned on doing that. However, I'm not using dados for the shelves, but rather (as your drawing pointed out) for registration/alignment. The rabbets at the corners are just to maintain aesthetic/stylistic consistency. Heck, even the grain direction will match on this particular unit

Now that I think of it, with the center panel going almost the entire length of the top, right down the center, there's a lot of support built in right there anyway...hopefully that would mitigate any strength issues from a top piece shorter by 1/4" per side

Link to comment
Share on other sites

5 minutes ago, Dubya said:

I'll have to look that up. I saw this article, which recommended 1/4", so I planned on doing that. However, I'm not using dados for the shelves, but rather (as your drawing pointed out) for registration/alignment. The rabbets at the corners are just to maintain aesthetic/stylistic consistency. Heck, even the grain direction will match on this particular unit

Now that I think of it, with the center panel going almost the entire length of the top, right down the center, there's a lot of support built in right there anyway...hopefully that would mitigate any strength issues from a top piece shorter by 1/4" per side

Not saying it's wrong but i would take a lot of that strength test with a grain of salt. for 1 none of his shear tests were actual sheet tests they were all bending tests. The failure mode tells you more then any sort of "strength" numbers he listed.

1/4" would probably be best. As far as strength goes if you build it right i doubt you'll ever load the thing enough to get close to it's failure load.

If what i drew is similar to what your doing the square at the end that i labeled as, not adding much strength, might look good as a 1/2" x 1/2" banding so the same amount of solid banding is shown in both directions.

Also thanks for that Frank Howarth video link that was a good vid.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Who's Online   1 Member, 0 Anonymous, 53 Guests (See full list)

  • Forum Statistics

    31.2k
    Total Topics
    422.1k
    Total Posts
  • Member Statistics

    23,779
    Total Members
    3,644
    Most Online
    Thanikanan
    Newest Member
    Thanikanan
    Joined