uh oh tenon started to pull out a few weeks after glue up - what to do?

[hugh lonner]

I am building a cabinet that will have a big granite top on it (about 300 lbs including everything on top). The legs are roughly 2" square and the tennons are just under 1" deep. there are 4 tenons per leg - two at the top and two at the bottom - ie the most obvious way to build a frame for a cabinet. The holes do meet for the two tenons, but in theory the tenons don't although perhaps I was not as careful as I should have been?

Anyway, I glued it up with floating panels and all was well. I started finishing it a couple weeks later (it is cherry, with cherry ply panels) and a week in noticed that on the left side panel the bottom tenon (towards the back) has pulled out between 1/8 and 1/4 of an inch. I can't figure out why this would have happened weeks after the glue up unless somehow the oil finish did something odd, or finishing the panel caused it to float in an odd way, but still it seems odd. Pushing or pulling on it does not seem to move it at all either in or out using a little, but not excessive force.

My basic question is do I leave it be and glue in a small piece to hide the gap or do I take a clamp and pull it back together at risk of breaking other bonds?

Any advice is welcome

[Lee Schierer]

Unless you can move it now, I doubt it had anything to do with your finish, it probably happened while the glue was wet. If your tenons were tight you could have built up pressure inside the mortice because the air couldn't escape. This air pressure pushed the joint open after the clamp pressure was removed too soon.

Put a clamp on it and see if it will move. If it does, move it out as far as you can get it, apply some glue and then clamp it closed. Leave the clamps on for at least 12 hours.

[Paul Symchych]

If you used PVC glue, simply regluing it without removing all the old glue will be dodgy.
A mechanical solution after you force it back together would be to cross peg the joint with a hardwood dowel. I often do that as much for the decorative effect as anything. With cherry I usually use a 1/4"-3/8" walnut or some dark wood dowel. The joint is then very unlikely to pull apart.
You would have to peg all of the M&T joints to keep the look constant. But I like the look. Just me.

Edit: an afterthought. Could it have been forced apart by the panel? Is the panel ply or solid? If solid the panel could have expanded the joint apart.

[Sam Murdoch]

If you used PVC glue, simply regluing it without removing all the old glue will be dodgy.
A mechanical solution after you force it back together would be to cross peg the joint with a hardwood dowel. I often do that as much for the decorative effect as anything. With cherry I usually use a 1/4"-3/8" walnut or some dark wood dowel. The joint is then very unlikely to pull apart.
You would have to peg all of the M&T joints to keep the look constant. But I like the look. Just me.

Edit: an afterthought. Could it have been forced apart by the panel? Is the panel ply or solid? If solid the panel could have expanded the joint apart.


Very likely the culprit. Are your panels truly "floating"? In any event what to do now? As Lee suggests glue and clamp and as Paul writes - peg the joint, but if your panels are not loose they will crack later or cause other grief. :(

[hugh lonner]

I think they are floating a little too much to the point where this one wasn't floating - ie I think I pushed it a little too hard when finishing and the center popped out of the groove and was tight against the leg just outside the groove. They are 1/8" cherry plywood.

Thanks for all the suggestions so far and especially the peg idea - I do love the way pegs look although I've always been a little scared to do them for fear of messing up a joint that was working well, but this might be just the incentive I need!

[Bobby O'Neal]

Got any pictures?

[hugh lonner]

I do. Let's see if these are sufficient. The first more or less just gives context and the second has the problem issue up close. The color is, of course, not very accurate, but for some reason my pictures of my projects never come out the right color. Also, obviously the top is not the real top - just a sheet of plywood and the drawers don't have their false fronts yet. None of that, of course, has anything to do with the problem, but uploading pictures to SMC instantly puts me in the mood to apologize!


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[scott vroom]

He stated that the panels were cherry plywood.

[Pat Barry]

I suspect that the glue joints may have been starved for glue due to a too tight fit. If that's the case with this joint the others may be the same. Can you pull it together as suggested by someone else? If so, I agree to carefully pull apart, re-glue, and pin it / peg it. I would do them all the same.

[David Posey]

Hugh, are you familiar with the drawbored M&T? I guarantee that joint would not have failed if you'd used it, so long as it were properly executed. There are examples that have held up for 3 or 4 centuries, and many of those were done in wood that was still green. You really wouldn't even have to use glue.

[Chris Friesen]

Hugh, are you familiar with the drawbored M&T? I guarantee that joint would not have failed if you'd used it, so long as it were properly executed. There are examples that have held up for 3 or 4 centuries, and many of those were done in wood that was still green. You really wouldn't even have to use glue.

With tenons only 1" long I'd be leery of drawboring for fear of blowing out the short grain at the end of the tenon. Personally I would have offset the tenons towards the outside and made them as long as possible, mitering the ends so they don't quite touch each other.

[David Weaver]

If I didn't want the look of a drawbored tenion, I would do a hidden wedge tenon. you'll never get it apart again, but I'm assuming you don't want to.

[David Posey]

+1 to both of the above suggestions. I think you might have to move the tenons towards the outside of the board to get the wedge to work right. I don't think it would work too well with mitered ends. If you do attempt a wedge tenon, make a practice peice first. You only get one shot to fit it.

[Jim Matthews]

Is this intended for your home use, or a customer?

If it's your home use, attach a glue block cleat on the "inside" corner beneath the bottom rail and use some screws to hold the cleat in place while the glue sets.
If it's for a customer, also scarf in a cherry face on the front rail with your best grain match to hide the gap. I'm guessing you glued this together upright, and the legs splayed when the panel was inserted.

(Not that I would know anything about assembly errors, first hand.)
(Not that I will admit, anyway.)

Lastly, this is a quality piece. It's the sort of thing that makes hacks like me take up the Tuba or Ice Fishing...

[hugh lonner]

Thanks to everyone for the advice and Jim you made my day with the compliment. It is indeed just made for myself. I'd go broke if I tried to make money woodworking.

I had not heard of drawbored tennons, but now I have and they totally make sense as a general principle (although in this case I didn't want to break the 15 good joints and based on what I read I don't think you can create them without doing that.

In retrospect I agree that I probably should have pushed everything out and mitered the ends of the tennons, but for aesthetics I thought centered was the way to go (foolishly, I know since "form follows function"). Not sure why I didn't miter them.

Anyway, I have now got some pegged tenons and I love the looks. Below is a picture of the gap, now essentially gone (the clamp made it go away with no trouble - it is clear the glue in that one joint was not functioning).

Then a further away shot of the overall effect of the pegs after sanding down and then finally a shot with one coat of finish on to show the contrast that already is popping out. Again apologies that the color in the photos is nothing like the color in person - you can just imagine new cherry with a clear finish and new walnut pegs...

Thanks again to everyone. They say a woodworker is no better than the mistakes he can fix and thanks to SMC I'm better off in that respect than I was a before posting!

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[Pat Barry]

Looks good - nice fix and nice project!

[frank shic]

it'll be an intended feature to everyone else that sees that beautiful cabinet. nice recovery!

[Brent VanFossen]

That's a nice cabinet and a good-looking fix.

[Jim Matthews]

They say a woodworker is no better than the mistakes he can fix and thanks to SMC I'm better off in that respect than I was a before posting!

But what do they know? They'll also tell you you should dry fit everything before glue up, and keep your tie out of the varnish.
This is a nice save... it looks planned. Take extra care to seal the exposed endgrain of the pegs - they'll draw finish in like a wick.