How hot is too hot? Ishi, a Native Californian and consummate craftsman who lived during the late nineteenth and early twentieth centuries, was disgusted with himself if he scorched an arrow shaft while straightening it. The wood should be heated hot enough to be uncomfortable to the touch but not hot enough to discolor.
Straightening the middle of a shaft is relatively easy because you have a "handle" on both sides but what about the ends of a shaft? Push down on the short end of the shaft with a small stick.