Solid Walnut bookshelf dados - is glue enough?

[Bill Brammer]

Building 6 ft high, 28 in wide, 12 inch deep solid 3/4 inch walnut bookshelf , no adjustable shelves. I have dados for all shelves. The sides are a little bowed, requiring some pressure with clamps to pull them together with the dados. Not a ton, but some. I'm trying to decide if I need to add screws with plugs or pocket screws (never used them) or if glue will be adequate. The dados are roughly 5/16 inch deep.
Trying to avoid screws from the outside with plugs because the wood is beautiful, but I would do it.
Have never used pocket screws, but I can learn.
Or is glue enough?
I've searched and searched on this with no luck.

[Michael Drew]

Did you already cut the dados? If not, have you considered another technique, like dominos? Or possibly sliding dovetail dados?

How many shelves and at what spacing? Glue may be just fine, depending on the spacing.

[Bill Brammer]

Thank you! Yes, I already cut the dados. 5 shelves plus the top and bottom, so averaging 10-12 inches apart.

[Ron Selzer]

I would glue it up

[Darrell Bade]

Have at it .......... glue it up.

[Brian Tymchak]

How much bow do you have in the sides over their length?

[Mike Hollingsworth]

With that many shelves at 5/16 you've got enough glue surface for sure.

[Bill Brammer]

The gaps I’m pulling closed are maybe 1/8 in tops

[andy bessette]

The gaps I’m pulling closed are maybe 1/8 in tops

I wouldn't be concerned about pulling down that small a gap. However, if you cut your own plugs from the original scrap they will certainly not take away from the finished assembly. I use Fuller counterbores and plug cutters.

[Derek Cohen]

Building 6 ft high, 28 in wide, 12 inch deep solid 3/4 inch walnut bookshelf , no adjustable shelves. I have dados for all shelves. The sides are a little bowed, requiring some pressure with clamps to pull them together with the dados. Not a ton, but some. I'm trying to decide if I need to add screws with plugs or pocket screws (never used them) or if glue will be adequate. The dados are roughly 5/16 inch deep.
Trying to avoid screws from the outside with plugs because the wood is beautiful, but I would do it.
Have never used pocket screws, but I can learn.
Or is glue enough?
I've searched and searched on this with no luck.

Bill, it appears to me that that issue is the bowed sides, and that these need to be reinforced to ensure that the shelves do not drop out if the sides continue to move.

I would not use dowels, screws, Dominos, or similar to connect the dado and end of shelves. The risk is that these will pull out of the end grain.

What I would consider is to attach (glue and screw) a short brace/stretcher below a dado and across the centre of the case on both side. Then connect these two braces with a stretcher using a dovetail at each end. The construction can be hidden under a shelf. The aim is to prevent the sides from pulling away and outwards. I hope my description is clear enough.

Regards from Perth

Derek

[Carl Beckett]

I have a couple cases where one shelf is rigidly fixed part way down (or up ;) ), and the remaining shelves are on pins. Similar to what Derek points out, pulling in something rigid shortens the distance for warping.

I would NOT plug from the outside. (thats me, just would not do it I am not a fan of the plugged look). If you want something very simple, pick one of the midway shelves and simply add a cleat underneath each end where it meets the sides (even though in a dado it doesnt matter). Glue/screw that cleat to the side. Then glue/screw that cleat to the shelf. It does not have to be a large cleat and does not have to go all the way to the front edge either.

Having said all that, glue alone 'might' be enough depending on how it wants to behave over the years (I have had drawer front dovetails loosen over time so it sometimes surprises me)

[Gordon Stump]

Glue away!!

[Bill Brammer]

Good grief I wish I’d asked this earlier. I’ve been cruising through YouTube and the Internet. This is great. Thanks everybody. I might add a cleat or a stretcher, I’ll see what it feels like when I glue it up.
Good to get an opinion on those plug cutters, I don’t have any but I will have need of them so I appreciate that

[Jamie Buxton]

Does the bookshelf have a back? If it does, that will pull the sides straight.

A back also adds big resistance to wracking, so it is a really good feature on several issues.

[Michael Drew]

Does the bookshelf have a back? If it does, that will pull the sides straight.

A back also adds big resistance to wracking, so it is a really good feature on several issues.

I was going to suggest this. Mostly for the racking issue you mention, but it's also a good way to keep the piece square during the glue up.

I'd also recommend that you think through how you will glue this thing up. With the amount of pieces you will be working with, and dados, and their respective lengths/widths, glue up will be a bit of a challenge to get everything correct. You can use TB3 to give you a bit more time, but in my experience, there is not much more forgiveness with TB3 as 1 or 2...... An extra set of hands would be helpful, if that's an option. I never do have help, so I am always thinking about how to do something solo when I really should have some help.

[Derek Cohen]

The back will only prevent racking. It will not help resist the sides bowing outwards.

You need a brace which pulls the sides inwards. This is why I suggested a stretcher (hidden below a shelf) at the centre, which is anchored at each end.

Regards from Perth

Derek

[Bill Brammer]

Yes 1/4 in back in a rabbet. , I was going to use quarter inch crown staples five eights inch long and maybe a little glue. Wondering how much glue if any and if I glue or staple the back to the shelves or just the rabbet.

[Bill Brammer]

And yes I’m waiting for a woodworking son-in-law for glue up. I know better than killing the marriage over this one😐

[Alan Schwabacher]

If you don’t want the brace below the shelf, a fairly common approach is to include a couple of through tenons at the ends of the shelves, extending beyond the dados. If you wedge the tenons into mortises wider toward the outside of the case, it can resist a large amount of pullout force. I believe Peter Korn referred to this as an Alan Peters joint.

[Jamie Buxton]

The back will only prevent racking. It will not help resist the sides bowing outwards.

You need a brace which pulls the sides inwards.



We agree. You need something to pull the sides inwards. That's a back. A back is usually a big sheet of plywood fastened all the way around. Staples work. Glue works. Okay, you have to put a clamp or two on the sides to make them straight while you fasten the back on.

[Lee Schierer]

If you can remove the bowing with light finger pressure, you should be good to go. Between the glue and the back panel the sides should stay in place. If it were my project, I would glue it asap with a helper. Dry assemble it so your clamps are all pre-adjusted to the size you will need.

Most important that you check the diagonal dimensions once you have it clamped before the glue sets up. DAMHIKT.

[andy bessette]

...glue up will be a bit of a challenge to get everything correct...An extra set of hands would be helpful...

Epoxy makes this easy.

[johnny means]

Use cauls to evenly clamp front to back on each shelf. One your glue is dry, your golden.

[Dave Sabo]

Epoxy makes this easy.

Only at the glueup stage.

At the finishing stage it’ll become a nightmare dealing with the inevitable squeeze out in the corners , and working inside a carcass.

[andy bessette]

...At the finishing stage it’ll become a nightmare dealing with the inevitable squeeze out in the corners , and working inside a carcass.

Nah. This cleanup is taken care of at the glue-up stage, before the epoxy cures.

[Derek Meyer]

You could try the Norm Abrams method, where he sets the shelf in a dado and then uses a pin nailer to shoot nails through the shelf and into the side. The pins are tiny, and the head is right up against the vertical side, so they are pretty much invisible. This will mechanically fasten the shelf to the side and help provide resistance against the side pulling away from the shelf. Norm used this method on a lot of carcasses he built for different projects.

[Bill Brammer]

Johnny, I've seen cauls on youtube. Sometimes people put a little curve in them. Do you think that is necessary?

[Jim Becker]

Bill, curved cauls exert more pressure in the middle where there can be no clamps. That keeps things flatter while the glue sets. An alternative is a taller caul that has more strength in that direction.

[Thomas McCurnin]

The sides are probably bowed. While Derek's approach is better, I would not hesitate to throw a few number 8 wood screws and into the center of the bow, which ever shelf that is, with the holes countersunk and plugged. Screwing into end grain is an acceptable technique, and was used in a Paul Sellers rocking chair I recently built, to attach the rockers to the end grain of the legs.

[johnny means]

Johnny, I've seen cauls on youtube. Sometimes people put a little curve in them. Do you think that is necessary? I make my cauls straight and then use a shim or two in the middle to create pressure btween the clamps. The cauls should be stiff enough to press out the cup, but flexible enough to bend and crapply pressure at both clamps.

[Bill Brammer]

Shims! Much easier than making and storing bowed cauls.. Thank you

[Tom Bender]

Bowed Cauls! a couple swipes with a plane, easier than shims.