I was thinking about Easton vs AMO spine yesterday and desided to make a peice of equipment that would yield both results. This is so simple I just had to share it. You can put your own twist to it to meet your own personal needs.
You need a board 30" long, a field point, metal insert, metal coat hanger, and two of the ends you cut off of old arrows.
Measure and find the center of your board, market. Measure 13" both directions from center and 14" from center mark those. Now drill 4 holes, one at each of the "from center marks". These should be drilled the same size as your cut off arrow peices.
Place the two leftover arrow peices in the 13" from center holes as pegs. Lay an arrow across them and mark a horizonal line in the center.
Now take the coat hanger and cut the bottom from it. You should have a straight wire about a foot long. Bend one end at 90 deg about twice the lenght of your field point. Now drill a hole thru the field point sideways that is the same size as your coat hanger wire. Place the wire thru the hole and slide it all the way to within 1" from the 90 deg bend. The bent peice should be pointing out the same direction as the point of the field tip. Your arrow will rest on this for measurement. Glue these two together.
Drill a hole in just above the center mark on your board the size of whatever insert you selected. Place the insert in the hole and screw the field tip and coat hanger wire in place. Once the field point bottoms out it will begin to turn the insert. You'll use this as a stop for the movement of the meter. Keep twisting so the "L" or bent peice of the coat hanger lines up with the bottom of the arrow (the mark you drew on the board)across the pegs. Now test to be sure downward presure on the "L" unscrews the field tip. You are using the threads as a bearing.
Now screw the board to the wall and us it as follows. Place the pegs in whichever holes you want to use for 26" or 28" spine measurements. Lay an arrow across the pegs. The center of the arrow will be laying on the coat hanger "L". Place your 2 lbs weight for 26" ot 1.94 (880 grams) weight for 28" centers on the arrow and take your reading.
For the scale you can either use a known good arrow and mark the line for a go no go test (using several arrows would give you all the ranges needed), or use the protractor method found on the other spine meter build along on this site.