Messed Up some Rails/Stiles - Best Way To Recover?

[jonny round boy]

Over the weekend, I cut/machined some 25mm thick poplar stock for a set of kitchen cabinet doors I'm making. This is the first set of doors I've made in this style since I discovered Festool...

After cutting to length, I cut 8mm domino slots in them (25mm deep in the ends of the rails, 28mm in the stiles) roughly centred in the stock (minus the 13mm depth of the groove this makes it perfectly sized for a 8x40 domino). Then I cut grooves in all the pieces, and cut the tenons on the ends of the rails HOWEVER the grooves & tenons are off centre as I wanted a 12mm panel depth. This has resulted in the following joints:

[attachimg=1]

As you can see, the domino joint is half-way across the edge of the tenon/groove. I made a sample joint in this way a couple of weeks ago, and everything seemed fine with this arrangement, however I only assembled it dry. In retrospect, it's obvious that I should have placed the domino in the centre of the groove.

Now I've come to glue the doors up, I've found that they won't go together properly, as the domino is essentially pushing the joint sideways:

[attachimg=2]

So I've now got a full set of doors that I need to glue up, but I don't want the same thing happening on all of them. My question is, what do I do now? The way I figure it, I have four options:

Option 1 - Glue the joints up without fitting the dominoes, and rely solely on the tenon for strength (the tenons themselves are a nice snug fit);

Option 2 - plane/sand the dominos down so they're thin enough not to put any sideways pressure on the joint (which may totally negate any additional strength they would have contributed?);

Option 3 - re-cut all the mortices slightly lower/higher, again so that the domino doesn't exert any sideways pressure;

Option 4 - glue dominoes in all the mortices to plug the holes, re-machine the pieces, and re-cut the mortices centred on the groove (I really don't want to do this, it'd be very costly in terms of time and dominoes).

Option 1 would be the easiest, but I'm concerned about the strength of the joint (if I were to do this it would have been better not to bother with the dominoes!!!). The tenons are 72x12mm (3" x 1/2"), less approx 1/6th where the domino is). I'm unsure if this will give sufficient glue area.

I need to get these glued up in the next day or two, and I don't have the time or the stock to re-make them all. What should I do now?

 

[PaulMarcel]

You seem to have a lot of long grain to long grain surface for glue with the tenons and groove.  I'd leave out the Domino and move on.

If you really want the Domino in there, glue it in one side of the joint.  When dry, try assembling the joint dry to see which side is pushing.  Sand just that side in place until you get a clean assembly then glue it up.

If you don't want to do the sanding idea but want the Domino, use thickened epoxy and a 6x40 Domino instead. The thickened epoxy will perfectly fill the void between the thinner Domino and the mortise and naturally fill the offset mortises.  Key is to not try to completely fill the mortises and get squeeze-out of the thickened epoxy mucking up the rest of the glue-up.  Just don't use a 5-minute epoxy; sure it is thickened and I've done this trick with it, but your glue up is more involved than mine was so that 5-minute timer may not be really kind.

I'm betting you flipped some stock and got the reference surfaces flipped.  Though you centered the mortise, any discrepancy between true center and what you had would be doubled if you flipped one board and it would be enough to do what you are seeing (just guessing).  Don't ask me why I know that

 

[mastercabman]

Don't bother with dominos

Why did you use them at the first place? ???
Either use M&T or Domino    NOT BOTH

#4 would be my choice.

 

[ajones]

Jon

As above leave out the dom,s you only need one or the other anyway.

If you have a misplaced domino mortice  which sometimes happens I remortice with a larger size and fit a suitably shortened domino and then mortice again with the correct size  [wink]

I too think you must have flipped some stock have you checked them all for fit it may only be a few that are bad..

 

[mouppe]

re option 4, if you still want to use dominoes, glue one in one half of the mortise and then use a flush cut saw and chisel to cut off the half sticking out. You only need to redo one half of each joint. Let it all dry and then remortise the hole correctly. This will only work if you have done the original mortise on the narrowest setting.

 

[jonny round boy]

Thanks for all the replies!

As to why I decided to put a domino in there at all, I figured that the mortice & tenon joint alone might not be strong enough given it's only 12-13mm deep. Seems I was wrong about that.  [embarassed] I do have a tendency to 'over-specify' things, and try to make things much stronger (and more complicated!) than perhaps they need to be. Lesson no.1 learnt!

As for the domino pockets being cut from the wrong side, I'm confident that's not the case due to the way I marked everything up & did the cutting. Also I think they would be further out of line if that was the case (I didn't try to get it dead centre, just somewhere near). Having looked at it again in detail I think it's just a case of the width of the domino pushing them apart, due to the offset nature of the joint, combined with a slight (approx. 0.2mm) offset of the groove & tenon whilst machining. Lesson no.2 Learnt!

Although I did a mock-up/sample of the joint, I should have gone as step further & made a full sample door, and glued it up. That way I would have found out about this problem earlier. Lesson no.3 learnt!

I've just glued another two doors up without the dominoes in at all. Both went together perfectly. I'll check them once they're dry, but I'm now sure they'll be more than strong enough.

Thanks again for the advice.

Jonathan

 

[rnt80]

Looks like you've got your answer.  K.I.S.S.

 

[Rob-GB]

Jonathan, I would have done the same as you, put a domino in to add extra security to what is in effect only a tongue and groove joint not a mortise and tenon joint.
In theory it should not be a problem and certainly was not on a job I did a while back.
Was the adjustable angle fence on your domino exactly at 90 degrees? I managed to lock mine off a tad out once but realised on the dry fit.
I would have probably glued the dominoes into the rails then shoulder planed them flush to the tongue to see if that helped, while scratching my head as to why it was not working as planned. [scratch chin]
Hope the rest of your project goes well.
Rob.

 

[farms100]

you have to love operator error.

a stub tenon would have been fine unless the doors were large and or heavy.