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The photos below point out a problem I’ve run into with the boxes I’ve been making.  The pictures show two boxes.  One is made of kiln-dried cherry and measures 11 ½ x 7 ½  x 3.  The other is made of kiln-dried maple and measures 12 ¼ x 8 x 3 1/8.  Both have badly twisted lids.   All the wood used was free of defects such as twisting, warping, or cupping.

<img src="http://i1074.photobucket.com/albums/w420/jihhwood/cherry%20barrel%20hinge%20box%202_zps1qawhedk.jpg" border="0" alt=" photo cherry barrel hinge box 2_zps1qawhedk.jpg"/>

<img src="http://i1074.photobucket.com/albums/w420/jihhwood/maple%20barrel%20hinge%20box%202_zpsbxqpjzrt.jpg" border="0" alt=" photo maple barrel hinge box 2_zpsbxqpjzrt.jpg"/>

 
In both cases, the lids are “frame-and-panel” construction.  The panel consists of a 1/8” plywood substrate, veneered on both sides.  The veneer on the underside is a single piece in both boxes.  In the case of the cherry box the veneer on the upper side of the panel consists of a single piece.  In the case of the maple box, the veneer on the upper side of the panel is made up of shop-made veneer – thin pieces I arranged for aesthetic purposes to look decorative and colorful.  
 
Before the glue-up, the lid panel was put into position (I cut a rabbet to house it).  I spot glued the panel at the mid-point on the “short” sides of the rectangle.  I left room in the rabbet for the panel to move feely. 
 
The box was glued up; afterward, box and lid were separated at the table saw.  I used 8 mm Soss hinges to attach the lid to the carcase.   The lid closed perfectly.
 
Finish was three coats of paraffin wax.  (To avoid darkening the hue of the wood, I did not seal it with super-blonde shellac – something I usually do when I make furniture and frames.)
 
The completed boxes were put on a desk (out of direct sunlight) in a spare bedroom.  We have oil hot-air heat, and do not keep our home very hot (63 daytime, 55 at night).  Nevertheless it has been cold where I live (a couple hours north of NYC) and humidity in the house does vary quite a lot (it was a low 29% this morning, for example).  When I inspected the boxes a couple of hours ago (the box had sat on the desk for a few weeks), I discovered that both of the lids no longer sit flush to the top front edge of the carcase.   They appear to have twisted, as the photos show.
 
I am stumped as to why the lids have twisted.  I asked myself these questions:
(1) Did I allow enough room for the panel to move if it wanted to?  I think I did.  (2) Did I glue the panel into the rabbet too generously or in the wrong location?  I think not.
 
Thanks in advance for any guidance you can provide – either why this happened or how to “failure-proof” boxes that I am yet to make!

The panels should have no movement to accommodate.

Inside the inset, and outside the entire top, check all corners with a known good square. Are they all? Unequal length of members, or not square corners will both net you a twisted finished product.

DAMHIKT

Is the decorative panel floating on the substate or glued to it? Not sure where I'm going with this but it's all I can think of at the moment.

Papa Jim

Did grain patterns go opposite of the outside skins and mirror each other? I've had this issue when using ply if you don't do that.

I think packer guy is sniffing in the right direction here; something about those panels is causing the warp. The diagonal grain of the veneer is overpowering the not-exactly-opposing grains of the ply. This could work if your surface veneer was very thin (like purchased veneer is) and substrate relatively thick, but I am guessing your shop made veneer is thicker and thus has enough power to overwhelm the ply whose strength is not opposing the force directly but only diagonally. Ply grain direction and veneer grain should be at 90 degrees to each other.

BTW if you have a stable veneered panel with ply substrate you ought to be able to glue it in all around. There should be no movement needing accounting for. I do this with bottoms all the time; makes a stronger box.

When you tested the lid during your dry fit, was everything square and plumb?
What is your glue-up process for the lid?
Could you have racked it during the gluing?
Uneven pressure can do it.

(12-24-2016, 10:23 AM)TomFromStLouis Wrote: [ -> ]I think packer guy is sniffing in the right direction here; something about those panels is causing the warp. The diagonal grain of the veneer is overpowering the not-exactly-opposing grains of the ply. This could work if your surface veneer was very thin (like purchased veneer is) and substrate relatively thick, but I am guessing your shop made veneer is thicker and thus has enough power to overwhelm the ply whose strength is not opposing the force directly but only diagonally. Ply grain direction and veneer grain should be at 90 degrees to each other.

BTW if you have a stable veneered panel with ply substrate you ought to be able to glue it in all around. There should be no movement needing accounting for. I do this with bottoms all the time; makes a stronger box.

Thanks for a clear explanation that makes sense.  I did use a thin plywood substrate (1/8 inch), and the colored strips I glued up were, as I recall, appreciably thicker than typical veneer.  So, as you suggested, my shop-made veneer may well have "overwhelmed" the ply substrate.  I think it's pretty clear that the frame material is not the culprit.  Nor are the finish or the hinges, etc.  It's got to be the veneered panel.  So . . . . it's back to the shop.  In each case, I'm going to remove the warped lid and make a new one, using a thicker substrate and shop-made veneer that's the same thickness as the conventional piece of veneer I've used on the underside of the lid.  If I'm careful and a little "creative", I may even be able to find good grain matches (lid-to-carcase) and even re-use the Soss hinges.  Wish me luck---and thanks again!

(12-24-2016, 10:51 AM)Gary G™ Wrote: [ -> ]When you tested the lid during your dry fit, was everything square and plumb?
What is your glue-up process for the lid?
Could you have racked it during the gluing?
Uneven pressure can do it.

Dry fit and gluing were "dead on".  Also, both the lid and the carcase were square.  As to the process of gluing I used the method usually recommended for mitered boxes -- butting the miters, tape on the outside... fold up the sides, etc.  I've used this method with success in the past, and I'm certain no irregularities creeped in during the glue-up.  Whatever happened, it occurred over several weeks following the successful (I thought) completion of the project.  I welcome your thoughts, however, so . .  . thank you for any additional ideas.

Given what's been said to this point, I'd agree it's probably the veneer.