Working With Thick Lumber

[Andrew Hughes]

That's a cool looking table but I hate the shiney finish. What is the deal with that? It makes the wood look like plastic.
Good luck with your build.

[Jim Becker]

I know this is a snarky response but how in the heck does one not have the tools to make a dovetail, yet has a domino xl? Scratching my head at what seems to be the cart before the horse but I guess I can somewhat see it?
Dylan times they are a changin just popped into my head.

Making a heavy sliding dovetail on the end of a structure that beefy is something that requires a bit of work. The table in the OP's photo looks to be somewhere between 3" and 4" thick! The shoulder cut could be relatively easy on the table top, but the angles add some fun to create the male side of the dovetail on that table top. A specialized hand plane would historically get this job, but most folks don't have something like that lying around. It may or may not be easier to put the male side of the sliding dovetail on the breadboard end as it could conceivably be machined on a shaper with a tall fence, and a jig used to hold a very beefy router with a big-butt dovetail bit to cut the slot on the end of the table top after making a multi-stepped relief cut with a straight bit.

Personally, I'd do a standard breadboard end, just beefed up proportionally to the table thickness. Or leave it as a slab farm table without any breadboard end.

[Prashun Patel]

Because you have a Domino, I would use Dominos. Make the mortises in your breadboard all at the tight setting. Make the tenons in the table tight in the center and then progressively wider as you go out to the sides. Glue all the tenons into the breadboard but only the center one in the table. I like the aesthetics of pinning all the tenons. I've used cut nails, screws from the bottom, or dowels.

Make the tenons 2/3 of the way into the breadboard and also that same distance into the table. While this is not necessary for the breadboard to assist in keeping the table flat, it will assist in resisting breaking when people apply weight to the ends or (Heaven forbid) try to lift the table by its breadboards. I'm not basing that recommendation on solid engineering knowledge, only on anecdotal experience on the few bb's I've made.

I would sooner to a spline than a wide mortise. Just easier to cut and route or plow than excavating a mortise (for me).

[Brian Holcombe]

Making a heavy sliding dovetail on the end of a structure that beefy is something that requires a bit of work. The table in the OP's photo looks to be somewhere between 3" and 4" thick! The shoulder cut could be relatively easy on the table top, but the angles add some fun to create the male side of the dovetail on that table top. A specialized hand plane would historically get this job, but most folks don't have something like that lying around. It may or may not be easier to put the male side of the sliding dovetail on the breadboard end as it could conceivably be machined on a shaper with a tall fence, and a jig used to hold a very beefy router with a big-butt dovetail bit to cut the slot on the end of the table top after making a multi-stepped relief cut with a straight bit.

Personally, I'd do a standard breadboard end, just beefed up proportionally to the table thickness. Or leave it as a slab farm table without any breadboard end.

I agree with this, and further it would not be easy with a hand plane.

In addition;

Sliding dovetails are pretty weak in this type of orientation, they need a wide grip to be strong and work against the leverage being applied to them when someone leans on the breadboard end, or as Prashun mentions, if anyone attempts to lift the table by the ends they will split. I've turned them upright and that makes them very strong, but it's highly impractical on a dining table.

If breadboards are a must, it's actually not very difficult to make a tongue using a router. Then cut the tongue down into a short full length stub tenon and three longer tenons. The outside tenons need considerable room side to side. The center tenon is what locks the breadboard on, the others can be pinned so long as the pin hole in the tenon is a elongated side to side in a considerable amount (big tables move a lot).

The trick to any joinery, especially that on a large table top is to make the table top accurate and especially without cupping. This allows you to mark from the top using it as a reference and do so with confidence.

[Scott DelPorte]

YouTube has some pretty good videos on how to do breadboards, although I have never seen one that deals with a top this thick. When laying out the tenons and peg holes on the ends, it’s useful to plan for how much wood movement you will get due to seasonal changes. I use an online calculator (think it’s called shrinkulator) to figure out the dimensional changes between 20 and 80 pct RH for the particular wood and top width that’s being used. Also like to peg them from the underside so they don’t show on the top. As for using sliding dovetails to attach battens instead of breadboards, it’s pretty straight forward to do with a router if you want to go that route.

[Prashun Patel]

If the other folks are concerned about the thickness, then Domino XL is even looking better; use double rows.

[Mike Hollis]

Because you have a Domino, I would use Dominos. Make the mortises in your breadboard all at the tight setting. Make the tenons in the table tight in the center and then progressively wider as you go out to the sides. Glue all the tenons into the breadboard but only the center one in the table. I like the aesthetics of pinning all the tenons. I've used cut nails, screws from the bottom, or dowels.

Make the tenons 2/3 of the way into the breadboard and also that same distance into the table. While this is not necessary for the breadboard to assist in keeping the table flat, it will assist in resisting breaking when people apply weight to the ends or (Heaven forbid) try to lift the table by its breadboards. I'm not basing that recommendation on solid engineering knowledge, only on anecdotal experience on the few bb's I've made.

I would sooner to a spline than a wide mortise. Just easier to cut and route or plow than excavating a mortise (for me).

Thanks Prashun, this sounds like the way I will go. From a design perspective, how wide do you folks think the breadboard should be? The top will be made up of 4 planks, each about 11 1/2” wide or so.

[Yonak Hawkins]

...how in the heck does one not have the tools to make a dovetail, yet has a domino xl?

For a huge end like the one pictured, a simple dovetail bit in a router would not do the trick. It would have to be a large, likely hand chiseled behemoth. Those look like 16/4 planks with, maybe 7" ends.

I think I would consider bolts in pockets.

[Jim Dwight]

I sketch things like that out to scale and play with it until I like the proportions.
The domino idea sounds good to me. I have a hall table with a 1 inch thick top made of oak. I followed the plans in a fine woodworking which called for screws to hold the breadboard ends tight which are covered by decorative caps of walnut - deliberately show. The screws other than the center are in slotted holes but still pulled up tight. The table is 10 years old or so and the breadboard ends are still tight. You might think about a few screws like this, capped by matching plugs if you don't want them to show or possibly a contrasting plug if you like the look. The advantage is to keep the breadboard end tighter to the boards going in the opposite direction. You cannot glue the whole mortise/tenon connection but you can screw it - with slotted holes to allow movement in that direction. With dominos, I would glue to the boards going the long direction and then have screws going through the breadboard end into the dominos.