The Spine-O-Meter Design Advantages
Archers are often confused when comparing traditional wood spine with aluminum or carbon spine because they are measured with two different methods. The Spine-O-Meter Deluxe is designed to translate between the two different spine “languages”. Now, if you want to know what carbon or aluminum shaft is equivalent to a 60-65 wooden arrow, the answer is readily available on the scale.
The Spine-O-Meter Deluxe measures arrow shafts using the Archery Trade Association (ATA, formally AMO) standard and the ASTM deflection is calculated from this result. The scales are marked with ATA pounds spine, the deflection of carbon and aluminum, 300, 400, etc. and the aluminum shaft size. This allows for fast and easy comparison of all types of shafts.
The traditional ATA spine test method uses a two pound weight on the shaft supported at a 26 inch span. The “modern” method, ASTM F2031-05 “Standard Test Method for Measurement of Arrow Shaft Static Spine (Stiffness)”, uses 1.94 pounds with the shaft supported at 28 inches. Using bending theory of beams and a little algebra a translation between the two methods has been incorporated in the design of this spine tester. The Spine-O-Meter Deluxe is the Rosetta Stone for arrow shafts.