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Help with bookshelf from all walnut

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Forum topic by BB1 posted 10-29-2017 02:04 PM 445 views 0 times favorited 13 replies Add to Favorites Watch
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BB1

856 posts in 687 days


10-29-2017 02:04 PM

I am in need of some insights from the LJ community once again. I am putting together a small bookcase for a friend. The wood is walnut harvested from his farm so there is some sentimental value to the wood. I am trying to make the entire bookcase from the walnut with no plywood or other materials. I have done a dry assembly as shown in the pictures.

I used dados for holding the shelves and I realize I cannot glue those entirely in place due to potential wood movement. I have used rabbits in the side pieces in order to hold the long pieces across the back (sorry if I’m not using the correct terminology for all of the parts). There will be “openings” between the back pieces (which should account for any wood movement while also giving some visual interest.

My question is can I attach the shelves to these back pieces in order to hold everything together? I have included some pictures showing the rabbit joint that I have to hold the back pieces to the sides.

I am planning on gluing and either using very small screws or finishing nails to help hold the back boards in place again while allowing for some wood movement. I I was thinking that if I could also attach the shelves to these back pieces that would give stability to the bookcase while still allowing that shelf to move forward if there was any movement that occurred in those pieces. The dimensions are about 30 inch tall by 30 inch wide and the shelves are just a bit under 12in deep. Any insights would be appreciated.


13 replies so far

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jonah

1471 posts in 3138 days


#1 posted 10-29-2017 02:20 PM

Typically with a solid wood back people use ship lapped joints (overlapping + alternating rabbets) on vertical back pieces, with only the center of each piece held in place with a nail, screw, or dab of glue. Horizontal back pieces you’ll need to do something similar to avoid gaps appearing as the wood contracts.

You’ll want to glue only the back part of the shelf dado to allow the shelf to move in and out.

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BB1

856 posts in 687 days


#2 posted 10-29-2017 02:50 PM

Thank you for that information. Quick followup question, if I’m planning on about 1 inch spaces between the horizontal back pieces (which will be centered behind each shelf) I assume I’m accounting for what ship lap would typically address? Will it be ok to glue the shelves to the horizontal back pieces along the whole width? Or would it be better to use screws or another method?


Typically with a solid wood back people use ship lapped joints (overlapping + alternating rabbets) on vertical back pieces, with only the center of each piece held in place with a nail, screw, or dab of glue. Horizontal back pieces you ll need to do something similar to avoid gaps appearing as the wood contracts.

You ll want to glue only the back part of the shelf dado to allow the shelf to move in and out.

- jonah


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tomsteve

667 posts in 1058 days


#3 posted 10-29-2017 02:56 PM

if the wood has been dried and the moisture content is low, then you shouldnt have a problem with glue ups.

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a1Jim

116592 posts in 3416 days


#4 posted 10-29-2017 03:02 PM

Hi Jonah
If the grain runs the same direction as the sides your fine gluing them in place it’s only with cross grain situation you have to be concerned with damage from wood movement, like your back you should use nails only, no glue. You don’t have to connect the back to the shelves they’re plenty strong to hold a lot of weight given you have such a short span unless your customer is going to be storing 30 gold bars on each shelf.

-- http://artisticwoodstudio.com Custom furniture

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BB1

856 posts in 687 days


#5 posted 10-29-2017 05:02 PM

Jim, I was thinking that attaching the shelves to the horizontal back boards would give stability to the whole case. I’m a bit worried if the rabbits connecting the horizontal back boards to the sides are sufficient (sounds like glue in the middle plus a screw or nail is the way to go for the back boards).


Hi Jonah
If the grain runs the same direction as the sides your fine gluing them in place it s only with cross grain situation you have to be concerned with damage from wood movement, like your back you should use nails only, no glue. You don t have to connect the back to the shelves they re plenty strong to hold a lot of weight given you have such a short span unless your customer is going to be storing 30 gold bars on each shelf.

- a1Jim


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Jim Jakosh

19804 posts in 2945 days


#6 posted 10-29-2017 05:15 PM

I have screwed a back board into the frame and the shelves without any problem, but I did not glue it.
I think you might want to put a front frame on it as well to hide the dadoes! It will give it a more finished look.
Even a strip of veneer glued all around would trim it out. That works good when I use oak veneered plywood for the sides. It hides everything.

You said the wood was harvested from their farm. Has it been air dried for a while or kiln dried?? I don’t think you want to put it into cabinetry if it is as all green.

Cheers, Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

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a1Jim

116592 posts in 3416 days


#7 posted 10-29-2017 05:53 PM

As far as making it less likely to rack, even though you said you don’t want to use plywood I would use a face frame and or a plywood back that covers the whole back, but that means you would have to invest in a sheet of walnut plywood, a 1/4” ply would add lots of strength.If you use ply you don’t have to worry about wood movement you could nail and glue it in place.
To me having the gaps in the back pieces really makes the project looks like you ran out of material, if your going to use solid wood just make the back solid no gaps and shoot it on with 18ga nails again no glue the nails will bend with wood movement where screws may not unless you install them in elongated holes. If you leave the top and bottom about an 1/8” away from the top and bottom then you shouldn’t have the back sticking out with seasonal changes. One thing you didn’t mention is it the wood has been checked for its moisture content?

-- http://artisticwoodstudio.com Custom furniture

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jerryminer

811 posts in 1281 days


#8 posted 10-29-2017 07:04 PM

You don’t have a wood movement issue between the sides and the shelves—they both will move front-to-back and won’t conflict with each other. You can safely glue them together (but you won’t get a lot of strength from this end-grain-to-face-grain joint)

You don’t have a wood movement issue between the shelf and the back piece—they are oriented in the same direction and can be glued together without problem.

You have a slight issue at the back piece-to-side connection as this is a cross-grain situation. But the back pieces are fairly small in width. Usually, anything less than 6” does not pose a serious wood-movement issue, but to be extra safe, you could use screws or nails here.

You are correct that the space between the back pieces will allow each board to expand/contract individually and avoid wood movement issues.

You’ll be fine. Your bookcase should last a lifetime.

-- Jerry, making sawdust professionally since 1976

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BB1

856 posts in 687 days


#9 posted 10-29-2017 07:46 PM

Jim – I will check with my friend about the face frame. I went back and forth in my mind about that. I have seen a half dovetail that was left showing. I realize a dado isn’t as visually appealing though.

tomsteve, Jim, and a1Jim – the wood has been air dried for years (per my understanding), but is something to be double-checked.

a1Jim – thanks for the added information and insights and the suggestion of using the 18ga nails.

jerryminer – thanks for the comments and additional insights on wood movement. Starting to feel like I can address the major potential issues. I indeed am hoping this lasts for a long time, thus all my questions. Building something for someone else is always a bit more stressful than when it is just for me, but looking forward to creating something that will be used regularly.

Thank you to all who replied. I really appreciate the help. Hopefully will have a completed project to post down the road.

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BB1

856 posts in 687 days


#10 posted 10-31-2017 01:09 AM

So, I checked moisture content tonight and and it was between 5 to less than 7. From what I know, I’m assuming that is pretty dry. Looking to glue in the shelves and then nail the horizontal back pieces to the sides in the rabbits I cut. I looked at adding some strips to cover the dados on the front and think that does give a more finished look. I have some cutoff pieces that will work nicely. Will check with my friend to see what he prefers.

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a1Jim

116592 posts in 3416 days


#11 posted 10-31-2017 01:30 AM

That all sounds like good news, it’s very dry and the back nailed on and glued in shelves should be fine.To me strips along the edges are better than exposed dados but look rather like a first time build, but a face frame makes it much stronger and their easy to make, you just pocket screws the face frame on the back of the rails into the stiles and nail it on ,glue it on or even biscuits to put it on.

-- http://artisticwoodstudio.com Custom furniture

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bondogaposis

4482 posts in 2190 days


#12 posted 10-31-2017 01:36 AM

You can glue the shelves into the dados because they will move in the same direction and amount as the sides. No problem with that.

-- Bondo Gaposis

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BB1

856 posts in 687 days


#13 posted 10-31-2017 01:49 AM

Thanks again for the help with thinking this all through. LJ to the rescue once again!

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