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How much cross-grain is it okay to glue?7/10
I am doing a kitchen in solid cherry, where the doors will have breadboard ends. I plan on doing a tongue and groove joint all the way across where the breadboard meets the panel. I’m wondering how much of the joint I should glue.
I’ve seen recommendations to glue about the third of the width of the joint... but this is for a dining table, which can be 40” wide... so that would mean about 13” worth of cross grain gluing. So, assuming this recommendation is sound, would that make it reasonably safe to glue, say, an 11” breadboard joint all the way across its length? Because I don’t see the difference between 11” of width out of the middle of a wider table top, and 11” of width comprising an entire door. Right?
I’m not looking for any guarantees, or an exact scientific number that’s going to hold in all situations. But I don’t think anybody would worry too much about gluing a 4” wide table apron all the way across its width. So what’s the rough cut-off where you’d start to worry about cracking? 6”” 8”? 10”? 12”?
I’m leaning towards gluing the middle 10”, and for doors wider than that, making a spring joint on the breadboard piece, so the ends theoretically stay tight without glue or mechanical connections.
Several things one , usually aprons do not get glued to full size wood table tops typically they get screwed on . The other thing about a spring joint for the breadboard ends the problem is not keeping it tight to the solid door but when the panel or door grows and shrinks the ends will not stay flush in many cases .
You will have no trouble gluing all the way across, IF there is no moisture change in the wood. From personal experience, I sure wouldn't cross grain 10". As for a spring joint all that does is put continuous stress on the joint.
I have made 10" to 18" wide cutting boards of strips of quartered Hard Maple for over 40 years. The boards have cross grain ends that are glued full width with an integral tenon on the board and a groove the length of the end cap. Every one I know of is still perfect, except for one I threw outside to self-destruct. Glued with TBIII or urethane or epoxy or resorcinol or u/f glues.
And these all have minimal finish - mineral oil, maybe. And get wet repeatedly and dry out. Some are never used ("too pretty!"), but still live in a working kitchen.
I regularly glue 12" wide foot rails on exterior doors to stiles, usually with a coped mortise and tenon joint, and have yet to see any crack or joint failure. This is usually in pattern grade Honduras Mahogany, an extremely stable wood that has almost no cross grain movement. I have Mahogany exterior doors in my house with 12" wide panels that have not cracked paint/finish from movement in 12 years of use/abuse.
Point is? There are no absolutes. Do some experiments. Look around with the Shrinkulator - try several things.
If you want to do breadboards on table tops, learn to hide/feature the movement with a spline and offsets the way Greene and Greene did on their work. They also used slightly offset pegs in slotted holes.
The Greene & Greens solution is elegant, hides slight offsets. I think David's photo is of the dining table @ the Gamble house in Pasadena. Go there if you are ever in CA.
The Greene brothers used screws to hold there bread board ends on and covered them with ebony plugs.
nicko - You are right about both the Thorsen Table and the screws. I had forgotten the the Halls did actually have to make this stuff, and make some money, so they used screws in many of their pieces.
Hiding or disguising the offset is the key.
Nathaniel, as a general rule of thumb you cannot glue cross grain any solid wood ever! It will split every single time. Might take a year or two but its inevitable. Take the time and peg the joint. Imo your only other option is one trim head screw in the center.