Do you round off tenons to fit routered mortises or chop the corners off?

[Brian]

Bevelling the corners is fine. Don't need to round 'em.

[Mitch Berkson]

OK. Good point about the right angle grains. But unless you're using silicone caulk to hold things together, isn't the glue going to try to prevent any movement? Maybe this is an argument for pinning that side of the joint and not using glue.

Mitch Berkson

[Larry Jaques]

On Fri, 16 Jan 2004 11:40:23 -0500, "Mitch Berkson" brought forth from the murky depths:

That 1/16" is for glue squeezeout, not movement. Glued joints don't move too awfully much.

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[Mitch Berkson]

You wouldn't think. But at 1:17 in the video, he says that the 1/16" is to allow for wood movement.

Mitch Berkson

[Noons]

Er... Right angle grain is not cross grain. That is a common mistake. What is cross grain is when you have end grain against long grain. As in the *end* of the tenon against the bottom of the mortice. Long grain against long grain, which is what a M-T join mostly is, is never a problem. Or else M-T would not be a strong join. And it is one of the strongest.

[gandalf]

-------------- Actually that reference is regarding the width of the tenon, not the length.

[Larry Blanchard]

Er.... Huh???

I guess they really do think differently in Oz :-).

[Larry Jaques]

On Fri, 16 Jan 2004 21:57:26 -0500, "Mitch Berkson" brought forth from the murky depths:

I meant tenon length/mortise depth difference but I see i nthe video he's referring to tenon width. I still disagree, though I'm sure I've made fewer M&T joints than Lon has.

What did you expect from a Californian? They have all sorts of movements out there.

Nah, I don't buy it. You've chipped dried squeezeout off a joint before, right? It's far too solid to allow movement of that magnitude. When glue joints are tested, the _wood_ fails before the joint does in most cases.

Ian Kirby disagrees.

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[Noons]

No. It's the same everywhere. Short grain is the end-grain. Long grain is along the grain.

You must NOT glue short grain to long grain. Nor short grain to short grain. It won't work.

But you can glue long grain flat to long grain, at any angle you may care. That's how M-T works, how lapped joints work, how virtually every wood glue-based join works.

Think about it, you'll see what I mean.

[Lawrence Wasserman]

You can glue it and it will be storng for a while, but if the joint is more than a few inches wide and the grain in the 2 pieces is at 90d, it'll split one of the pieces sooner or later. Otherwise, breadboard ends, for example, could be just glued on a T&G instead of pinned & allowed to 'float'