The flattening process
Woodworkers all have their own system for flattening wood, some of which are pretty complex. This is one simple method that’ll get you started. As you get comfortable with flattening, you’re sure to develop your own.
Step 1: Lay out the parts
Use chalk to lay out the parts you expect to get out of the board. Work around knots, cracks and edges with deep tree bark. If there are several parts coming from the same board, draw yourself a paper sketch to remind you of the layout. Then cut the board to lengths corresponding to the parts. Cut each part at least 2 in. longer than the final length. Do so even if knots, checks or cracks are part of the waste at the ends. That’ll allow you to remove any checks on the ends of the boards or snipe (gouges) left over from the planer. Don’t work with long boards unless they’re called for; it’s much easier to flatten short boards.