Can I use an Alluminum arrow to "calibrate" my scale to woods shafts?
Actually.... no. On spine testers, the supports for wood arrows are 26" apart. For aluminum, they're 28" apart. So, aluminum arrows sitting on supports that are 26" between centers will spine quite a bit stiffer thanEaston's publishedstandards.
The length of the arrow will not affect the actual spine reading.