Arrow Spine

[wislnwings]

I've got some wood arrows that I picked up a few years ago, second hand.  They are flying really good from my 66" Hill Redman that's 52@27. The problem I have is that I don't know what wood they are or what spine range they fall in and I'm down to about 6.  Without buying a spine tester, is there a way to figure out what they are?

[Longtoke]

no clue, just an idea but maybe you could do a paper tune test then consult with a spine chart to get a rough estimate of spine weight. Im sure some wood workers could look at the shaft and tell you what wood it is, or if you have a broke one the smell should tell you if it is cedar or not.....

[John3]

I know I've seen "homemade" spine testers over the years on the net or in a magazine. Google this or YouTube could help you.

I'll bet there is a trad guy near you somewhere that has a spine tester. Do you have a local archery forum in LA that you get on. If so, ask on there and you might find one close to you.

Bisch

[wjk]

"There are two kinds of spine (stick with us, we promise not to get too technical). There’s static spine, which is how an arrow reacts when an 880-gram (1.94 lbs.) weight is suspended from the center of the arrow. The arrow must be 29” in length and supported by two points, which are 28” apart. The number of inches the arrow deflects or bends X 1000 due to the weight is the spine size or measurement of an arrow. So, a 500 arrow bends .5-inches when the weight is applied.

Then there is dynamic spine, which describes the way an arrow reacts from the stored energy of a bow as it is shot."
Eastonhunting.com

Alright, but say I'm tunning the arrow, cutting it down 1/4" at at time and paper testing it. How do I figure out the spine now? On the one hand, who cares/ It works, and it's the right spine, but suppose I want to know, maybe for future reference or future changes in arrow selction. How do I figure out the spine of the arrow at 28" draw?

[wjk]

sorry i meant ot end it with 28" arrow length.

[Cavscout9753]

Well as for what wood, you could take a tip off and shave a piece of the taper and see if its cedar. If it doesn't smell like it then I guess itd be anyones guess if they're already stained. As for the spine without a spine tester, even if it could be done itd probably be more work and money than a test kit. This could be a great time to switch to douglas fir. As much as I hate tunning, tunning a Hill bow with wood arrows is about as easy as it gets. If you're not doing anything crazy with tip weight, starting at the draw weight and going up 2 maybe 3 spine groups (3 is likely too much anyway) should be simple enough.

[Bud B.]

Mail it off to an arrowsmith and have them duplicate the arrow x12.

And get an arrow test kit while you're at it. They are great to have.

[wislnwings]

Thanks guys.  Bud, that might be my best option.

[**DONOTDELETE**]

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Alright, but say I'm tunning the arrow, cutting it down 1/4" at at time and paper testing it. How do I figure out the spine now? On the one hand, who cares/ It works, and it's the right spine, but suppose I want to know, maybe for future reference or future changes in arrow selction. How do I figure out the spine of the arrow at 28" draw?
 

You can build a very accurate spine tester on the cheap using a dial indicator like this one and a magnetic base.

Just use a couple shelf brackets to support the arrows and you can get fishing weights to hang off the shaft or use a slide bracket easy enough...

Total cost less than $50 and it only takes a couple hours to get it set up. Then you are good to go.....

Even using carbon shafts, it's a really good idea to check your spine on every shaft and rotate them. Some of the carbon shafts out there are worse than woodies in spine variation.I've seen as much as .070 in a dozen carbon shafts.

 http://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html

[Basinboy]

I think Mr Stephen Raggio has a spine tester Craig.

[Fletcher]

Bud has the best idea.  I can spine a couple for you, but I'm not likely to get a set made anytime soon.