door cupping

Wood Dr

Cupping in a tabletop

Q. We made a table out of an 8 inch wide piece of lumber and I can guarantee that the top was flat when we shipped it, but now the customer has said that the individual pieces are cupped. Indeed, when I inspected it, he is correct. We were careful to make sure that all the pieces had the grain running the same direction (heart side down) to give a nice look. We did screw the top to the metal frame but the screws pulled out. What advice can you give?