Well, I ain't got a spine tester. Shoot fire, those jokers cost over a hundred duckets! Some are dang near two hundred clams or more. I can get a lot of arrow building supplies for that and even when I cull the flyers, I still come out ahead. I give the flyers to Navajo folks here who hang them above the threshold of their doors. They ain't gonna be shootin' 'em.
I got plenty of time out here on the rez to sit on my front porch stoop and make arrows. Ain't much else to do. Two and a half hours to the nearest town of appreciable size. Flip a coin, we going to Flagstaff, AZ or Farmington, NM? But the more I'm sittin' here making shafts, the more I'm learning by "feel" what shafts are going to be right.
Talked to an older Navajo guy yesterday who saw my arrows and was curious. He shared with me that the way the Navajo straightened their shafts was building a fire over sand. Then they shoved the shafts into the hot sand and straightened them while they were hot. They had a shaft diameter sizing tool and straightening wrench made out of ram horn. The hole was of the diameter of shafts that shot best from that particular bow so it was matched to the bow. They grooved the shafts with zig-zag lines to represent lightning. They used some type of shoots that grow someplace but so far, I haven't seen any that would work. One other Navajo guy told me Mountain Mahogany is what was used. He said the bows were sinew-backed Gambel's Oak. This dude showed me a bow he made like this, plus the arrows. The arrows had flared nocks and fletching was about 5.5" long and cut low and straight. The usual Navajo crest is black-red-black-red bands about 3/4" wide. But the zig-zag grooves cut into the shafts are the most important thing. Every Navajo I've talked to about arrows brings this up as being very important. Grooves help keep the shaft straight, but the fact is, it represents lightning and this is the reason put forth. Lightning and arrows are related to one another here.
There's a lot of archery-related lore still here. There's an article of jewelry here called a "ketoh" or "bow guard" which is a bracer. Thick leather bracer to which has been added silver and turquoise. I have two of these. The Hopi wear these also. Arrowheads are commonly worn or carried on the person for protection. A gift of an arrow or an arrowhead is very deeply appreciated.