One stray arrow..

Pydpiper · Post by **Pydpiper** » Sat Apr 12, 2008 7:45 am

Doing some fine tuning on my turkey arrows, slicks with grappler's. I can usually have these things grouping the size of a turkeys head to 40 yards (on the bench), and still do, all but one arrow.
The arrows are made exactly the same as the others, yet one arrow is hitting 2" lower than the rest at 40 yards. When I made this batch of arrows I did it the same as all the rest, I take all the components and weigh each piece, like the inserts, I put 6 aside, weigh each one, use the lowest weight and diamond file the others to match, then repeat this process with each component. I have never had a stray arrow before, and the bench is proving this one to be an oddity.
I have no idea what is causing this and would really appreciate some speculation.
I will simply discard the arrow, thats not the point, it is just eating away at me why it wont conform to my efforts.

Farmer · Post by **Farmer** » Sat Apr 12, 2008 8:03 am

Is it hitting the same point each time just low ? ( is this arrow grouping ) Are you using carbon or aluminum shafts ? You have weigh the components , have you weighed the bare shafts ? With all you have done, you would think they would be bang on .

Pydpiper · Post by **Pydpiper** » Sat Apr 12, 2008 8:20 am

Same POI every time, every component is exactly the same weight, carbon arrows, same placement of grappler's in relation to the blades.. There is not one Grain of difference from one arrow to the next.
I even went so far as to mark the stray arrow and shoot the batch without knowing which one was marked to avoid the possibility of this being psychological, that was defiantly a concern

.
I want to know what is up before I scrap this arrow so I can hopefully learn something from it.

Boo · Post by **Boo** » Sat Apr 12, 2008 8:29 am

Swap components.

Digger · Post by **Digger** » Sat Apr 12, 2008 8:38 am

Boo wrote:Swap components.

Had the same problem with my slicks, put another slick bhead on and it straightened itself out. I was using Laser ll carbons.

Stosh · Post by **Stosh** » Sat Apr 12, 2008 8:55 am

Can you spin it with a dial indicator on it? Could be bent more than the others, I had one gt that did the same thing, I put it in 2 vee blocks and it was .012 tir. Shot fp ok but not my slicks.

Hope this helps, Stosh

mtbyak · Post by **mtbyak** » Sat Apr 12, 2008 8:57 am

I have to agree with Digger

I have seen this with numerous different broadheads.

You may even find that, that specific broadhead may work fine on another bolt but not on that specific one

Shoot Straight
Kirk

Stash · Post by **Stash** » Sat Apr 12, 2008 10:43 am

Sounds like maybe your nock end isn't square.

Are you always putting the same vane down? If so, try putting another vane down and see if it hits high left or high right.

Normous · Post by **Normous** » Sat Apr 12, 2008 10:55 am

I've banged my head in the wall in the past regarding the same frustrating problem. One or two out of a dozen just don't doens't seem to follow the same program as the others. I have a dusty odds and ends arrow corner of the arrows that couldn't.

awshucks · Post by **awshucks** » Sat Apr 12, 2008 11:23 am

David, keep your eye out for an arrow staightener and make one of these by moving the dial indicator down to the end and reposition roller bracket. It solves mysteries, lol. When xbowking was here, he had a flaky arrow and we found out it was about .010" out of round right at the insert. I know most of y'all will laugh at this, but while you can take the boy out of the machine shop, you can't take the machine shop out of the boy, lol. Besides, David is well......David, the only guy I met more "ar" than myself.

[img][img]http://i61.photobucket.com/albums/h74/a ... test4s.jpg[/img][/img]

Pydpiper · Post by **Pydpiper** » Sat Apr 12, 2008 11:56 am

Pretty sure you just called me anal retentive..

I have the G5 arrow straightener, my arrow ends are very square to the inserts/nocks. I also use a dial indicator like the one in your picture (stole the idea from you

) I also have a tool to roll my arrows, not as fancy as that aluminum job of yours, I still live in the marble/2X4 days.
The arrows roll true, nock/insert are flush, I have tried repositioning the broadhead by loosening and twisting the washer but nothing has made a difference.
I can fix this quite easily by swapping parts, that is not my concern. My goal is to understand why this is happening when I know that each stage of the assembly is equal to the consistency of the parts. I can change components, but I am thirsty for an answer first.
Anal retentive? I make sure each arrow is built in the same temperature/humidity level, I use a timer to insure each vane is pressed on at the exact same pressure for the exact same amount of time and thanks to awshucks I even know how to measure the weight of the glue on each vane.
Consistency + consistency should equal consistency. This 2" drop on one arrow out of the 26 I have that are identical has me scratching my head.

shafferm · Post by **shafferm** » Sat Apr 12, 2008 12:33 pm

Sounds like it could be due to a manufacturer variation in the spine of that one arrow. Have you tried doing a static spine test for your arrows to see if they all behave the same?

awshucks · Post by **awshucks** » Sat Apr 12, 2008 12:46 pm

Well, if you ever figure that problem arrow out, you can then figure out how spinning the washer on a Slick Trick eliminates or adds run out. I've miked the washers, there's not a thick or thin side to them. I solved a few of my mysteries this fall when a forum buddy wised me up to the fact that some GT shafts are smaller on the o.d. than others, but have same i.d. Also shows up on scale, so know that's probably not your problem or you would have caught it by now. Some of you may remember a delimma[sp] I came across last year when my Zwickey grapplers were sliding up the shaft in flight out of my Phoenix, I used rubber o rings to stop it. The fact that the Phoenix was an Ecet and the shafts were undersize .007"explained that one, lol.

Pydpiper · Post by **Pydpiper** » Sat Apr 12, 2008 4:01 pm

shafferm wrote:Sounds like it could be due to a manufacturer variation in the spine of that one arrow. Have you tried doing a static spine test for your arrows to see if they all behave the same?

This is next on my list, I have no idea what would be considered accurate but my thoughts were to secure the nock and insert end and use a scale to measure what flex comes from "x" amount of weight from the center of pull and spinning it periodically to see if it varies.
If there is a more accurate way of measuring spine than what I am thinking I would be happy to hear it!

Boo · Post by **Boo** » Sat Apr 12, 2008 4:42 pm

shafferm wrote:Sounds like it could be due to a manufacturer variation in the spine of that one arrow. Have you tried doing a static spine test for your arrows to see if they all behave the same?

I bet that is it. Support the arrow and and add a weight in the middle and measure the relative deflection. Test it in four quadrants. I have two suborn arrows for one of my trad bows that is like that.