runout question

[Andy Cooper]

I knocked together an arrow spinner today...something I've never used before. How much, if any, runout is acceptable before flight is affected?

[Grey Taylor]

It may be difficult to quantify.
I have a birch arrow that is so bent it looks as if it's pointed off to the side when it's at full draw. But that arrow is one of the most accurate arrows I've ever used.
When I straighten wood shafts I go for the least visible wobble I can possible get. What that reads on a dial indicator is anyone's guess.

Guy

[Andy Cooper]

Then it seems rather a waste of time to straighten them and to tune the heads, doesn't it?

[Grey Taylor]

Absolutely not.
The birch arrow I have is an anomoly. I would never expect an arrow that bent to shoot well.
Straighten as much as you're comfortable with. If you have a dial indicator and feel the need to straighten to .007" runout, go for it.
All I'm trying to say is that a particular number may be hard to determine. The stuff we're using does not behave like a bench rest rifle.

Guy

[Fletcher]

I believe any runout will affect arrow flight, altho it may be so slight that you can tell.  On a Grayling type straightner I go for .005 tir.  I normally use a spinner that I can spread out to over 24 inches and straighten until I can see any wobble at the center or ends.

[jmack]

As an industrial mechanic, and former machinist, I do feel your pain. However, this is traditional archery, and it leans more towards magic instead of logic. Take a deep breath, and just let it ride. It's wood man, not rocket science! I think the spinners are actually meant more for checking broadhead alignment than for runout on a shaft. An arrow shaft is going to flex upon release, no matter how straight you get it, but if it's tuned right, it will overcome the paradox. However, if the broadhead has been aligned incorrectly, then you're going to see all kinds of mayhem.

[Andy Cooper]

Thanks for the insights. I realize wood is not going to be as straight as carbon or aluminum...at least in my hands. Won't a broadhead seem to be misaligned, though, if the shaft isn't straight? I'm not arguing, just trying to understand and to do things as well as I can. I used to just slap arrows together and go shoot or hunt. Now I'm learning tuning--both of my bows and arrows...or trying to! Thanks.

[Jeremy]

Have you ever seen the pictures of the snakey arrows shot from the snakey bows?   :D   I'll have to see if I can dig that pic up.

If the fletching is in line with the point, the amount of tolerated wiggle in the middle is very surprising.  That holds true for compounds too. You rarely find a bent shaft like that though.

[Andy Cooper]

Is the idea, though, that less runout at the tip of a BH correlates with better, more accurate arrow flight? Or have I missed the entire point of tuning the arrows?

[Old York]

In my experience, the correct spine trumps all, and a good arrow ranks above the world's best bow.

If one gets the shafts straight before tapering, then getting the broadheads true won't be so problematic. Straightness of shaft & trueness of BH are long-standing "givens" already.

Still, it's an interesting question being raised....at what point does a bent shaft/dodgy BH affect arrow flight?
The testing could take years and years, cost  thousands of dollars and take milllions of lives  

[Andy Cooper]

Originally posted by Old York:
The testing could take years and years, cost  thousands of dollars and take milllions of lives      

That wouldn't be a paraphrase from  Animal House , would it?   :cool: