Over and over I've read that cross grain glue ups are doomed to failure due to humidity and wood movement.

Of course it begged the question of how table aprons stay  connected to legs in mortise and tenon glue ups - some for hundreds of years too.

Anyway I decided  to see if I could wreck a cross  grain  glue up with wood movement

I put a  couple of pieces of wood together of differing thicknesses of Siberian Elm.

The glue Titebond III

Several times I soaked them  for days at a time in a bucket and left them to  dry in full sun  plus they spent a year out of doors in the weather.

 

Pic 1 & 2 is the glue up after a year.

Next pic is the  glue up in my vice with my trusty Trimo  wrench about to tear the joint asunder

And the results

I think it is fair to say that the glue line did not fail.

Next I suppose I should do a joint  that all the experts warn will absolutely positively  of a dead true certainty fail.

I'll try a nice wide glue up like bread board ends Not the cute little tenons the experts all recommend but full board with cross grain.  Maybe I'll get carried away and   do a regular glue up  like a regular bread board would have and see what that results in.

I think it's good to test the advice of the experts don't you?

Nice test, Cliff.

Just a side note regarding your last couple of paragraphs. Many years ago, I made a trestle style hobby table for a friend. It was all pine, 2 x construction. Made a breadboard end on the tops but due to my inexperience with the construction, I ended up gluing the breadboard ends on the table. Less than 6 months later, the top split. 

Now, I'm not saying it was the glue up that caused it. The 2 x came from the local Blue Borg so the moisture content is suspect and I suppose there could have been other factors as well.

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Lew Kauffman-
Wood Turners Forum Host

Time Traveler and Purveyor of the Universe's Finest Custom Rolling Pins!

Hmmm  now that's a definite possibility.  The force of  along-the-grain expansion in wood is rather considerable.

Maybe the experts know sumpin' after all.

The species of wood is of note. Some expand more than others though I must admit to failing at having an on-board catalog of which ones move more than others.

I wonder if there's a forestry department document  lurking on the interwebs somewhere on that topic.  They published  quite a substantial number of very informative documents  some many years back.  Though I fear, as of late, the pace of research and publication has diminished.

I may know who to ask.

Excellent test and amazing results.  Thanks Cliff for your work and reports.

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Fred
aka Pop's Shop
www.pops-shop.com
'Soooooo many patterns - sooooo little time'
Scroll Saw Forum Host

Hey guys, drill a few holes in the board and drive a few hardwood dowels with glue on them ( make sure you slot the dowel first) and that will hold just fine.

And cliff, next time please use pine for a test, I'd love some Siberian ANYTHING!!!!!

You want some? The stuff grows like weeds. It's a warm soft wood with lots of interesting grain.  Turns buttery  golden brown with a little BLO.  Like soft cherry.  Maybe a little softer.

You can see it here:

http://s1002.photobucket.com/user/zydaco/library/The%20Shop/A%20box?sort=3&page=1

and here

http://s1002.photobucket.com/user/zydaco/library/The%20Shop/more%20boxes?sort=3&page=1

 I had them loaded to TPW but in a flurry of rules about having titles on images they got dumped.

I'll message you.

Cross grain glue ups like in a mortice and tenon work because they are relatively short, even in a tenon it is prudent to leave some expansion room in the length of the mortice.  On a wider tenon such as in a table with a breadboard end that is fully glued, the glue will hold the wood in place while the wider piece that has the tenon on it probably will shrink and expand with differences in seasons due to diffenent humidity levels.  To test this do a breadboard end with pegged tenons and check it from the summer to winter, I would expect that the end piece will either be shorter or longer than the rest of the piece depending on the season.