The Spine-O-Meter Deluxe is the most versatile spine tester available.  The scale displays the ATA (formerly AMO) spine, in pounds, along with the deflection that would be measured with the ASTM method used for carbon and aluminum shafts.  Along the top, the deflection of aluminum shafts is displayed.  At a glance, all types of arrow shafts can be compared against one another to take the guess work out of choosing the correct shaft.
The original Spine-O-Meter was the first spine tester to incorporate the conversion factors to translate between the two different spine measurement systems.  After several years of production it has been retired in favor of the latest Spine-O-Meter Deluxe.
We continue to pursue improvements in the design of spine testers to make them easier to operate.  A new refinement to our current design is on the drawing board so check back occasionally to see what we are offering.
Original Spine-O-Meter

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.


Arrow Spine Translation

Deflection to Pounds Spine

Aluminum and Carbon Spine

The principle of the conversion between the two spine measurement systems is based on beam deflection theory.  The three links below are useful papers for understanding the conversion and comparing different shaft materials.
"Arrow Spine Translation" shows the mathematics to convert between the two systems.
"Deflection to Pounds Spine" compiles the deflection in either system to the ATA spine.
"Aluminum and Carbon Spine" compiles the parameters of these shafts in both systems.
Introducing the Spine-O-Meter Deleuxe
Pneumatic Version Price:   $340 USD
Manual Version Price:          $240 USD
Introducing the latest advance in spine testers.  This new design is an all-metal, precision machined instrument, ensuring accuracy, repeatability and a long service life.  The scale has been repositioned to place the zero mark at eye level and the spine readings straight in front of the operator.  There are two versions available.  For the hobbyist the manual version offers precision and versatility without breaking the bank.  For those who spine a lot of shafts the pneumatic version uses a cylinder to raise and lower the weight.  The cylinder is operated with a foot switch ? freeing the operator to handle and spine shafts more efficiently.  These ergonomic refinements make this the best spine tester available for high volume use.
Click on the close up of the scale for a short video showcasing the features of the Spine-O-Meter Deluxe.