joining large boards

[Lasse Hilbrandt]

Im going to build my first dinner table.

Its going to concist of two oak boards of 2x20x79 inches.

Whats the best way to join those boards together ?

Is it important how I turn each board against each other ?

The oak is kiln dryed professionally so the moister content should be low.

[David Utterback]

Have the edges of the boards been run through a jointer or otherwise straightened? With kiln dried wood and 2" thick, you should be okay with selecting the 2 best faces. It is important to use glue that is fairly fresh and clamp it according to the directions on the container.

We would love to see pictures.

[Doug Hepler]

Lasse,

Many woodworkers recommend that the boards used to glue up a panel be alternating bark side up, bark side down. I don't think that there is any basis in fact for this, just a theory about how boards cup when they dry out. IF the boards cup the surface will be ugly no matter how you orient the annular rings. You can prevent this from happening with kiln dried lumber by finishing both sides identically.

I agree with David that you should pick the best faces and not worry about which way the annular rings are facing.What is more important IMO is that you be able to plane the surfaces flush after the panel has been glued up. In order to do this easily the grain must be rising in the same direction on both faces.

I also agree that the edges that you glue up should be jointed. There is a trick to this, if you will be doing it with a hand plane. Choose your sides and then fold them together like a book. The edges that will be glued together are the spine of the book. Align them as evenly as possible. Begin in the middle and plane to one end, then the other. You will be almost done when you are getting shavings from both boards. Then plane once along the whole length. Repeat as necessary to get a well-fitting joint.

Doug

[Jim Becker]

Personally, I always choose the "display" view as the best face for each board, regardless of grain orientation, as Doug mentions. Presumably, you can compensate for any wood movement by construction technique of what supports the surface to insure it stays flat over time while still being able to move seasonally

[Wayne Lomman]

Since you are using only 2 boards, the growth ring orientation question is irrelevant. It is important with multiple boards but not this job.

Simply pick your best two faces and, as Doug says, ensure the grain is rising in the same direction on both boards. It will make planing and sanding much easier.

A simple butt joint and good glue is the best joint. If you wish you can add dowels, biscuits etc to help keep it aligned while clamping. I would be using resorcinol or epoxy glue. Cheers

[Roger Marty]

Why rescorcinol or epoxy rather than wood glue?

[Derek Cohen]

Im going to build my first dinner table.

Its going to concist of two oak boards of 2x20x79 inches.

Whats the best way to join those boards together ?

Is it important how I turn each board against each other ?

The oak is kiln dryed professionally so the moister content should be low.

Hi Lasse

Is the oak rough sawn? If so, how do you plan to joint and thickness the boards?

I would prepare the boards as much as possible beforehand, and then glue together.

The boards can be butt jointed and glued without biscuits, dowels or dominos (I usually use Titebond hide glue - it does not affect finishes and cleans up with water).

Regards from Perth

Derek

[Bill Adamsen]

Why rescorcinol or epoxy rather than wood glue?

I use epoxy for both red and white oak but it is alleged to be a poor adhesive for oak. Epoxy does have gap filling properties which neither resorcinol not aliphatic can claim. Resorcinol is exceptionally water and temperature resistant. It does have a long cure time and is dark colored. It requires exceptionally tight joints and strong clamping. Epoxy on the other hand requires the adhesive to fill the joint and should not be clamped tight. But then will leave a visible glue line, and coincidentally a glue line surface that may resist some (especially waterborne) finishes. Aliphatic glues work well with oak with minimal visibility. The aliphatic glues I use are all exceptionally acidic (who knew?) which - along with moisture and tannins - is I think why they tend to oxidize the shafts of many clamps (keep clamps from contacting wood). Not sure which glue I'd use ... probably the epoxy or aliphatic.

[Prashun Patel]

I like slow setting epoxy because it give a lot of time to clamp and set things.

I like using dominos, dowels, or biscuits on thick tops to help with alignment.

Use cauls to achieve even pressure along the whole length.

I orient for visual appeal. However I also take into account grain direction. I find the easiest way to flatten and level the seam and final panel is with a hand plane. Orienting for the same grain direction makes this easier at the seam.

I don't pay attention to the alternating growth ring orientation. On wide slab glue ups, you don't have enough boards for it to make sense even in theory. For narrow boards, it is easier and more advisable to select boards that are stable. This usually means picking things away from the crown of the curve. This has also the beneficial effect of facilitating grain matching.

[andy bessette]

Generally it will have a better appearance if the annular ring orientation is the same. Unless you can create near perfect joints, I'd use epoxy glue.

[John TenEyck]

Titebond glue or whatever you have that's similar. No need to do anything fancy. The only requirement is that the two edges mate well - gap free, and you use enough clamps to keep the joint tight while the glue dries.

John

[Wayne Lomman]

Titebond etc creep during polishing and over time. That's why I recommend epoxy or resorcinol

[Lasse Hilbrandt]

They are rough sawn.

I will most likely be using a jointer and then a thicknesser. The more I think about it, the more I think I will use dowels to keep the boards aligned and spacers on the dowels to keep a small space between the boards. It will look better I think, than gluing it up to one board.

[Andrew Pitonyak]

They are rough sawn.

I will most likely be using a jointer and then a thicknesser. The more I think about it, the more I think I will use dowels to keep the boards aligned and spacers on the dowels to keep a small space between the boards. It will look better I think, than gluing it up to one board.

So the boards won't actually touch, so you will not really be gluing them together. You will, however, have dowels connecting the two boards.....

My first thought is..... do you really need to connect them at all if you want a gap? I would be worried about the strength of the dowels holding the joint together when you move the table. To avoid this, you will attach the top to a base and those dowels will still be visible.

I would have people who have done split tops comment on how they handled this. I am not saying don't do it, I am saying get more information first.

[Lee Schierer]

If this is a dinning table and you are leaving a crack in the middle what happens if something gets spilled on the table and runs into the crack? How do you clean the surfaces and dowels? Will the table top set on a base of some type or will the dowels be supporting the weight of the top plus all the dishes and such that will be placed on the table.

[Phil Mueller]

Lasse, you may want to look up Japanese Furniture Maker George Nakashima. He makes a number of tables that consist of two slabs joined by dovetail keys (with a slight separation between the two). Here’s one example:

371126

[Lasse Hilbrandt]

Im making the table for a colleague. She want´s the crac. She wants steel legs as seen in the link below. I don´t think the dowels will do anything but keep the boards aligned.

https://planke-bord.dk/shop/bordben-stel-plankeborde-spiseborde/krydsstel-til-plankebord/?attribute_farve=Sort&gclid=EAIaIQobChMIyezrlrep1wIVSLHtCh2T2w8hEAQYASAB EgJTLPD_BwE

[Robert Engel]

The more I think about it, the more I think I will use dowels to keep the boards aligned and spacers on the dowels to keep a small space between the boards. It will look better I think, than gluing it up to one board.
I would reconsider this both for aesthetic and sanitary reasons.

Jointing long boards on a machine can be challenge, even on a long bed jointer. For boards with significant bows I've found it best to do the initial jointing on the TS with a fence extension and a good quality glue line rip blade.

Alternate faces against the jointer fence thereby cancelling out any error off 90°.

Fine tune the fit with a hand planes. Big fan of spring joints.

When gluing up panels, I generally don't use alignment aids, but for the dining table project I am working on I elected to use splines because I wanted to keep the top as thick as possible (and because I despise biscuits and I don't have a dowelling jig or a Domino).

Use a waterproof glue with a good open time like TB 3 or epoxy (for some reason I don't like epoxy on white oak). In my case, I chose to glue the top in 3 section rather than try to do it all at once. This greatly reduced the stress!!

Hope this helps.

[Prashun Patel]

I don't have an issue with a split top aesthetically or functionally.

However, I would not join it with dowels. I would instead use a batten or apron system to keep them aligned.

[Lasse Hilbrandt]

I don't have an issue with a split top aesthetically or functionally. However, I would not join it with dowels. I would instead use a batten or apron system to keep them aligned.
what is a batten?
I think a apron design will look out of place with the steel legs chosen by the customer.

[Wayne Lomman]

Lasse, having now seen the picture, your design is good the way it is. The steel legs will hold your top aligned at each end. All you will need is some locating pins in between. I recommend something like 10mm stainless steel pins. They only need to be glued into one side. Just buy some 10mm stainless bolts, cut the heads off and glue the threaded end into one side of the joint leaving the other side to slip into its hole when assembling the table. Cheers

[Pat Barry]

What will you do for bracing to keep the table from racking and wobbling?

[Mark Gibney]

I wouldn't use the dowels. You're adding a visual element that will look at best uninteresting, at worst like a mistake.

You don't need them. If your client grows tired of the gap, or want a wider gap a year firm now you can make the changes if the dowels are not there.
Being attached to the steel legs will keep the two boards aligned just fine.