STEP 3: TEST FOR TWISTING WITH WINDING STICKS
Set a pair of winding sticks (pronounced “why-nding”) parallel to each other on opposite ends of your board and site along the winding sticks. The winding sticks will make any twisting appear more exaggerated, showing you which corners need to be lowered.
Having dark ends or bars on one winding stick makes twist easier to spot. You don’t even need to make fancy winding sticks, but can simply use two straight pieces of wood that are the same size.
Use your pencil to mark the high corners. Because of how boards twist, the high corners will usually be opposite each other.
STEP 4: REMOVE THE TWIST AND FLATTEN THE FACE
Place your straight edge on the high corners to verify how much wood needs to be removed.
Use a longer fore plane (No. 6) or jointer plane (No. 7 or No. 8) to remove the high corners and check your progress with a straight edge.
If you are getting “tear-out”, that means that you are planing against the grain. Flip your board around and plane in the other direction.
Below are several options for handplanes for flattening the board’s face (from left to right): A Stanley No. 6 “Fore Plane”, a Stanley No. 7 “Jointer Plane”, a Stanley No. 8 “Jointer Plane”, and an 18th century style wooden jointer plane (I built it, so it’s my favorite!):
Your shavings will still be somewhat heavy in this step, but not nearly as heavy as with the scrub plane / jack plane.
Just don’t remove too much on the corners or you’ll have to lower the rest of the board to match your new low corners. Once the straight edge lies flat across the previously-higher corners, move onto flattening the rest of the panel face.
The longer handplane will uniformly bring the surface downward, skipping all the valleys that a smaller handplane would fall into. As you’re planing be conscious about not introducing a lengthwise arc.
HANDPLANING 101 TIP:
Here’s how to avoid getting “valleys” in the middle of your board when planing: When your handplane starts on the board, keep the downward pressure on the front knob of the handplane only:
When your handplane is in the middle of the board push downward on both the front knob and the rear handle:
When the front of your handplane moves over the edge of the board, remove the downward pressure from the front knob, and only push downward on the rear handle. For practice you can even remove your hand from the front knob:
Use diagonal passes, then lengthwise passes, periodically using a straight edge and your winding sticks to check your progress toward perfect flatness.
When you’re getting full length and full width shavings, and your board’s face starts to look flat and smooth, then you’ll know that the board is about ready.
The straight edge should show no gaps no matter which way you turn it on the board’s face.