Primitive Archer

Main Discussion Area => Arrows => Topic started by: Trapper Rob on November 17, 2012, 10:15:28 am

Title: Spine question
Post by: Trapper Rob on November 17, 2012, 10:15:28 am

I just bought a used spine tester never used one before what do they mean buy 26" centers I have some wild rose & viburnum to check.
Rob

Title: Re: Spine question
Post by: Pat B on November 17, 2012, 02:57:32 pm

The uprights on your spine tester are set 26" apart. That is the standard. It is set up for a 28" arrow with a 125gr point.  For each inch over 28" you can subtract 5# per inch from the actual spine reading , and you can add 5# per inch for each inch under 28".

Title: Re: Spine question
Post by: adb on November 25, 2012, 10:30:55 am

AMO spine values are determined by placing an arrow shaft on 26" centers, hanging a 2# weight from the middle, and recording the deflection of the shaft in inches.

Title: Re: Spine question
Post by: tdeland on November 25, 2012, 04:08:25 pm

@ Trapper Rob...
Do you know the deflection measures? like if my shaft bends 1" down with 2lbs, what is the spine weight? I would love to be able to test the spine on my arrows without buying a device.... I usually just guess right now.

Title: Re: Spine question
Post by: adb on November 25, 2012, 04:25:23 pm

I think one of the cedar arrow manufacturers has a deflection chart on their website. I think it's Rose City, but I can't remember. Google is your friend!!

Title: Re: Spine question
Post by: Pat B on November 25, 2012, 04:43:46 pm

Google James Hill Spine Tested. He has a deflection chart there you can copy.

Title: Re: Spine question
Post by: Dictionary on November 25, 2012, 05:42:43 pm

I don't meant to steal a thread here, but how important is measuring spine on our bows? I've been told, even if you spine an arrow for a 40 pound bow, other things are taken into account like handle width and shooting style. Just wanting to know as i have never bothered to properly spine an arrow before.

Title: Re: Spine question
Post by: Trapper Rob on November 25, 2012, 07:40:09 pm

Dictionary I'm the same never worried about it before but I bought a used spine tester & was trying to figure out how to use it because all my shafts aren't the same length.
Rob

Title: Re: Spine question
Post by: tdeland on November 25, 2012, 08:04:41 pm

thanks! it is 26/D=spine weight.

Title: Re: Spine question
Post by: adb on November 25, 2012, 11:01:11 pm

An arrow's known spine only gets you in the ballpark. After that, there are many variables to achieve good  arrow flight. Shaft length, point weight, feather style, string material, etc...
Proper arrow spine is more critical the less center shot a bow is. I find I have to drop a spine value for most of my longbows without a cut in arrow shelf. With a true center shot recurve, exact arrow spine is less critical. A very common misconception regarding traditional archery is, that little or no bow/arrow tuning is required. Not true! Once you have a bow/arrow combo that is properly tuned, the impossible is possible. Ask Byron Ferguson.

Title: Re: Spine question
Post by: Arrowind on December 05, 2012, 08:00:35 pm

Quote from: adb on November 25, 2012, 11:01:11 pm

An arrow's known spine only gets you in the ballpark. After that, there are many variables to achieve good  arrow flight. Shaft length, point weight, feather style, string material, etc...
Proper arrow spine is more critical the less center shot a bow is. I find I have to drop a spine value for most of my longbows without a cut in arrow shelf. With a true center shot recurve, exact arrow spine is less critical. A very common misconception regarding traditional archery is, that little or no bow/arrow tuning is required. Not true! Once you have a bow/arrow combo that is properly tuned, the impossible is possible. Ask Byron Ferguson.

I am just starting to learn this in an effort to improve accuracy.  Not trying to hijack the thread but are there any good "tune alongs" out there?