No it is not absolutely necessary to taper your shafts. One reason for doing it it to get weight forward of center, barrel tapered recover from paradox faster. If you go to the read only section of this site, you'll find a link to Jawge's site. That is where I got started hand planning my own arrows a couple years ago. He details arrow making, and gives sound explanations that should have you well on your way to making fine arrows. Plenty of bow building information there also.
