Author Topic: Shaft orientaion is spine tester  (Read 2793 times)

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Offline occupant

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Shaft orientaion is spine tester
« on: December 22, 2014, 12:04:03 am »
I have recently started making my own shafts. I made my own spine tester and am trying to get my last batch to spine close to 138#. Then it occured to me. Do I want the weight to pull on the arrow that would simulate the shaft bending away from the bow? I have already got the horn inserts glues in and the grain oriented so that if the shaft breaks it will, hopefully, not go through my hand. And if anybody really cares, the shafts are poplar 1/2" tapered to 3/8", 30 3/4" from base of point to bottom of nock, points vary between 230-290 grain, bow is 123-125# depending on how long it is strung.

Offline burchett.donald

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Re: Shaft orientaion is spine tester
« Reply #1 on: December 22, 2014, 02:02:17 am »
  occupant, You will want to have the grain orientation perpendicular to the bow...You will want to have the grain orientation perpendicular to the weight...
                                                                                                             Don
                                                                                                               
Genesis 27:3 Now therefore take, I pray thee, thy weapons, thy quiver and thy bow, and go out to the field, and take me some venison;

Offline steve b.

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Re: Shaft orientaion is spine tester
« Reply #2 on: December 22, 2014, 03:31:04 am »
I hang the weight such that it pulls the shaft "away from the bow", yes.

Offline willie

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Re: Shaft orientaion is spine tester
« Reply #3 on: December 22, 2014, 07:14:56 am »
 i have always been confused about some of the advice I have read because some of the slow motion videos I have seen. The videos show the arrow bending towards the bow when first released, and arrows that bend too much, breaking right above the bow hand. It seems to me that when testing spine, the tester would want to know how low the spine is on the weakest side so that he will not over bend an arrow especially if it is oriented the worst way. Many arrows I have spined, are quite a bit weaker if one looks for the orientation with the most deflection, yet most advice I have read, reccomends spining and judging the arrow by the stiffest side?

Offline steve b.

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Re: Shaft orientaion is spine tester
« Reply #4 on: December 22, 2014, 09:05:12 am »
There's plenty to read about, and plenty to be confused about, in this business.  I would follow the instinct that you get from watching the videos.
Personally, I tilt my bow when I shoot so the arrow is laying on the bow.  At release the arrow tends to bend sideways, around the bow, more so than it tends to bend up/down.  So I want the long lines of the rings of the shaft on the sides, resisting the deflection.
Most of my arrow flight problems are from the arrow wobbling side to side, not up and down, so there is a lot of energy in that direction.
When I spine the shafts I'm only interested in the deflection sideways, so I hang my weight in that direction.  If I spin the shaft 180 I get the same reading, if I spin it 90 I'll get a different reading.

Offline Pat B

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Re: Shaft orientaion is spine tester
« Reply #5 on: December 22, 2014, 09:32:35 am »
For doweled shafts you want the grain lines against the bow. Generally one of those two sides will be the stronger side. You also want the grain "flames" pointing forward. For safety sake that is the #1 orientation.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline occupant

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Re: Shaft orientaion is spine tester
« Reply #6 on: December 22, 2014, 10:27:45 am »
Thanks to all of you for the replies. I thought that hanging the weight to pull the shaft the way that it would bend away from the bow when shot would be the right way, but I wanted to find out from others what their thoughts were. Sorry for the mis spellings, I was half asleep when I posted it.

Offline willie

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Re: Shaft orientaion is spine tester
« Reply #7 on: December 23, 2014, 01:49:43 pm »


as the arrow needs to bend back the other way to clear the handle, so spine in that orientation probally needs to be consistent to paradox correctly also, so you are not wrong at all

as pat said,

  "Generally one of those two sides will be the stronger side."

I have found that there can be *quite * a bit of difference between the two weak sides,  as well as the difference between the strong and weak