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Straightening 'crown', (the curved face or edge of an extremely bowed board):)
Straightening an extreme crown is a successive approximation sequence. Successive cuts are made from each end, made successively longer each time the board is turned end for end. After the crown is straightened, the work piece would next be taken to a table saw for a cut to make a new parallel edge—which then will likely be smoothed by another run through the jointer.
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