Guy, these grooves go by various names; blood grooves being a popular term and more recently lightning grooves. There have been many suggestions about their origin/ purpose, but I don't think there has been a definitive answer for these. The most recent purported use is their function in keeping the shaft straight by hardening the raised surface while heat straightening. Your observation is about as valid as any other at this point. Most societies have some form of tradition that the purpose for its origin has been lost. With Plains Indians, which is really where this was common, there are a variety of different stories surrounding them. Most of these tribes used sanding stones to smooth their shafts, so smoothing them was not an issue in the 19th century. As stated, a specific tool was made and used to produce the grooves. The reasons behind some things may just be lost to time, but it's certainly interesting to speculate. In fact, it is interesting how often we accidentally stumble onto answers just by curiosity and persistence. Curtis