Ideas to flatten a warped table top

[s1nglemalt]

Age-old question: the bookmatched walnut live-edge table has warped 1/4" over 42" in each side. You can see I placed in angle brackets, but even they were moved. Some options include:

1. Get wider angle iron 32" across the span of the legs, instead of the 3" wide black pair on each end

2. Plane the top to appear flat, but that will still show a gap below

3. ?

I hope you can help. The wood is oil finished on both sides, and it was perhaps not dry enough, or it was. The top is only ~7/8" so my screws going into it need to be small.

[AceHoleInOne]

Was the wood kiln dried?

 

-Ace-

[Brendon_t]

That is quite a bow. 

Personally, I wouldn't try to muscle it flat. You may warp/break the base or crack the top before keeping it flat. 

If it were me, I would remove the top, rip in length wise along spots that would allow the best glue lines with the thinnest blade I could find then joint each edge to 90° and re glue.

Any idea what mc the wood was at? Unless it's dry enough,  it may continue moving. 

[drzaius]

What Brendon said.

[AceHoleInOne]

Or what you could do is cut kerf's in from the underside to relieve the stress and make it go flat. Then glue in some thin strips of wood to fill the kerf. Then hide the kerfs on the end grain with breadboard ends. 

-Ace-

 

 

 

[Greenaqua]

What Brendon said...

I had this happen to me on a nice 8/4 walnut board that I cut on a bandsaw and was planning on bookmatching.  The board was sitting in my garage for a couple of years and as soon as I cut it into two, the pieces started cupping.  Heartbreaking was how I felt and am hesitant to attempt a book match again unless I know I have enough thickness left over to flatten them after they cup.  Those cupped boards sat in my garage for another 2 years before I could move on with them and use them for something else.

 

[Pwk5017]

Throw it outside on your lawn with the concave side on the grass. Assuming you have a sunny/mild day, your top will move back to flat within a couple hours. Keep an eye on it, cause it will reverse on you!! Will this permanently fix your issue? maybe, maybe not. I did this on two different occasions, and the one time it worked like magic and held. The other time it worked like magic, but rebounded to half of its original bow after 48 hours. Still an improvement, but not perfect. I would attempt to coax it back into position using atmospheric differences(what got you here in the first place), and then resort to brendon's suggestion of remaking the top. You don't have much meat to work with there.

[Eric.]

It doesn't matter what you do, if you screw it back down the way it is now, you'll continue to have problems.  For the millionth time...you have to let wood MOVE, or THAT happens.  That top is locked down with no wiggle room, and it told you how happy it's not by warping horribly.  IMO it's beyond repair.  Start again and follow wood movement rules this time.

[AceHoleInOne]

The only way to prevent this from moving is to cut kerfs from underneath to relieve the stress in the wood. Using filler strips and glue them in is like a piece of rebar. You need a ridged glue line to prevent movement. If you see the board in the picture, it's the center of the tree, look at the grain. That is gonna move, no mater how you equalize with moisture. 

-Ace-