Tenons on a wide board (for the third time)

[HSteier]

Last year there was a good discussion re: tenons on a wide board. I was making matched Conn. highboy and companion lowboys. I ended up following Dennis Bork's advice. I glued the lowest tenon (so that it wouldn't move and knock off the knee block) and then pinned the middle and upper tenons using the draw-bore method to keep the joint tight. It worked like a charm.
But now I have another problem. I'm making two Phila. lowboys that will again require tenoning the side board into the leg. But these legs have inset columns. The leg post is 2" square, the columns are 1" diameter, so there is only 1" of wood to tenon into. So the tenons are only 7/8" long. This leaves very little room for a 3/8" pin. There would only be 1/4" on each side of the pin risking splitting of the tenon or the leg post. I'm tempted to glue all 3 tenons. So I'd like some input about the real world consequences of cross-grain glueing a wide board.
I'll confess my experience.
About ten years ago I was making a buffet that had a 20" wide top. After struggling to hand plane the board flat and square, I took a Skil saw to cut it to length and ended up cutting the board about 2" short.
Instead of taking an axe to the rest of the piece I made bread board ends that I tenoned to the top. I glued all the tenons. Ten years later all is  well and nothing has cracked. The top is walnut and is not quarter sawn so one would expect that it would have a fair amount of expansion/contraction.
So what is everyone else's experience? In the modern world where indoor temperatures and humdity are relatively constant year-round, do glued cross-grain joints hold up?

Howard Steier

 

[chamfer]

Hi Howard et al,

Some years back on OldTools, a similar discussion arose around a Mahogany desk, reputed to have been owned/used by Benjamin Franklin, on which the fall-front writing surface had clamped ends - presumably glued full length. The discussion arose precisely because the clamped panel had not split over the years, despite the apparent cross-grain construction.

This led me to get out my copy of Bruce Hoadley's _Understanding Wood_ in order to see if this phenomenon could be explained on some basis other than it being a fluke or a stroke of luck. After looking at various factors discussed in his text (elastic limit, compression set, proportional limit, etc.), I began to see that one could, indeed, identify relevant factors and quantify the likelihood of success or failure in cross-grain construction. I usually resist posting links to earlier messages on other forums, but, in this case, I think the lengthy text is (mostly) very germane to your question, and hope it will be acceptable to simply provide the link:

http://swingleydev.com/archive/get.php?message_id=105237#message

In brief, it appears that with properly selected and seasoned timber going into a predictably controlled environment, your experience is likely more than a happy accident. Add a good film finish, and your chances of avoiding structural failure increase dramatically. (Though, when making furniture for clients, with eventual environmental conditions beyond my knowledge/control, I felt I had to be much more cautious about this.)

Hope this helps ... and, at the very least, maybe it will generate some useful discussion.

Don McConnell
Eureka Springs, AR

 

[HSteier]

Thanks for the link.
After I wrote my post, I remembered that a Phila desk on frame that I did about 8 years ago with Gene Landon at Olde Mill had wide sides tenoned into the legs. There were a dozen students who did this project and I bet many read this forum.
Has anyone had any problems?

Howard Steier

 

[Adam Cherubini]

I think the lid on the Franklin desk in Don's OT thread is either not original or has been repaired.  What typically happens on desks of this age is the lid shrinks, but the breadboards don't and the hinges get yanked off.  It's very typical to see the flap shy of the ends and one or more patches where the hinges have been replaced.  This is especially so of the lids with mitered ends.  I always wondered why guys didn't put the hinges on the bread boards to prevent this.  I figured there would be too great an unsupported span between them, or too much stress on the little tenons that join the pieces together.

So though I have nothing to base this on beside the pictures, I suspect the condition we see that desk in is not reflective of a 250 year old desk.  I don't really think we should expect zero movement or zero cracking.  Cracks are pretty common on period furniture and we can see the carcass side cracked on this particular piece. 

After WiA, if anybody is still interested, I can go and take a closer look at this desk in particular.  And I can ask around at the art museum to see if anybody there worked on it.  Even the surface looks warmed over to me, so this might not be an actual example of the success of period cross grain joinery.

Adam

 

[awleonard]

I hesitate to jump in as I am very much a rookie.  I built a lowboy/dressing table out of walnut ala Phil Lowe class.  I glued all three tenons.  I wondered if it would work out ok when I did it.  The piece has been through a couple of season cycles so far and has exhibited no problems.  Well, not with the panel.  I have one knee block that moved with the panel and not the leg!  Live and learn.  Next time, I won't glue to the panel.  Anyway, its obvious there has been movement, but no splitting yet.  For reference, I live in Memphis.  The house temp. is resonably constant, but the humidity swings in the house are pretty high (forced air heating and a dry ambient air to start with).  Might reference his article on building his lowboy in FWW to see if he glues them.  I know he has built a whole bunch of these!  Freddy Roman frequents this forum, maybe he will chime in.  Between working with Phil and working on antiques, he has probably seen a few.

Tony