To straighten warped wood, use winding sticks to find twists and bowed areas, and then use a jack plane to level the surface of the wood. You need a flat surface, two winding sticks and a jack plane.
- Set up the winding sticks
Place your board on a flat part of the bench, and place winding sticks on top of the board at both ends.
- Look for twists
Look at the tops of the sticks at eye level. To locate twists, look for spots where one stick is higher than the other or sloped.
- Remove the twists
To remove the twists, run a jack plane along the surface of the board from one corner to the other.
- Set down a winding stick
Place a single winding stick at the end of the board so no light seeps through the bottom.
- Look for bowed spots
Slowly side the winding stick towards the other side of the board. Don't lift up the stick while sliding it. Look for instances of light peaking through the bottom to find bowed spots.
- Correct the bowed spots
Run the plane along the board lengthwise, shaving off non-bowed areas until the surface of the wood is level.