Arrow spine

mzombek · February 23, 2013, 07:47:00 AM

Hey guys,
I'm not sure if this is the correct place for this question. Anyway, do any of you know of a web site that shows how to build a tester and also explain how it works?
Thanks,
Z

Sharpster · February 23, 2013, 12:15:00 PM

Michael,

I'm doing the same thing right now. I'm not sure if I can post links but if you type these words into your browser: measuring arrow spine deflection, then in advanced search, under "None of these words" type in the word: Charts

You'll see a bunch of ways to make your own.

Ron

Sharpster · February 23, 2013, 12:35:00 PM

Sorry man I posted too soon.. Just search "Homemade arrow spine tester"... I found several different tutorials for making various designs. Try using the search feature here on TG too.

Ron

mzombek · February 24, 2013, 01:48:00 PM

Ron,
I am still trying to understand this spine stuff. From what I understand, the devise uses a 2 pound wt. to deflect the arrow. The distance of deflection with a two pound wt. is what your spine is. I understand the deflection in inches, but I don't understand what the numbers are that it is converted to represent.
Thanks,
Mike

WESTBROOK · February 24, 2013, 07:56:00 PM

Mike, the shaft will be suspended between points 26" apart. When the 2lb weight is hung on the shafts the needle will point to a number on the scale (deflection in .001 of an inch). Lets say a shaft measures .335" deflection, you divide the 26" spread by .335 and it will give you 77.6, that shaft has a AMO spine of 77.6lbs. That is how wood shafts are measured, Aluminum and Carbon are measured between 28" points with a 1.94lb weight.(that is the ASTM measurement)

Eric

Triphammer · February 24, 2013, 08:02:00 PM

Search here for a spine gauge or spine tester. there's several. seach the net & find dozens. Stone simple in theory! I built mine with info here & some ideas from some other sites then use my own idea for suporting the 2# weight.

mzombek · February 24, 2013, 08:06:00 PM

Ron, Eric,
I appriciate your explanation on a subject that only a newbie could ask.
All of you guys that answer these questions are so valuable to us less educated to this sport.
Thanks so much for you help.
Mike

WESTBROOK · February 24, 2013, 08:33:00 PM

Sure Mike, good luck with your project. If your building wood arrows, a spine tester is essential IMO, carbon and Alum are pretty consitent.

Eric