Arrow spine

[wvarcher]

My arrows always end up with the knock to the left in my target.  Does this mean my arrows are underspined? 

[BowJunkie]

Knock to the left is over spined,  Knock to the right is under spined
I have in the past, chucked them up in my cordless drill and used sand paper to thin them down.
What draw weight and length is the bow and what is the spine on the arrows?

[wvarcher]

My bow is 55lbs at 28".  I have a 27.5" draw.  The bow is 72" ttt.  It is a bend-through-the-handle elb.  I am gonna say it is about 1 1/ 8 inch wide at the handle.  Thanks

[BowJunkie]

Ok, when you say a 27.5 draw,,, are you measuring from the bottom of the groove in the nock
to the back of the field point/ broad head?
If so you should have 27.5'' plus the field point / broad head = 28-28.5'' neighborhood
If not and they measure shorter this will cause the shaft to be stiffer / over spined.
Options... 
1. new set of arrows
2. Thin the shafts down one at a time till they fly correct,
3. add more draw weight to the bow by Toasting the back,,  maybe not an option if it has a backing applied.
If it were me I would thin the shafts, easiest and less work, or buy a new set of shafts
If anyone else has other ideas or more experienced please feel free to chime in here.

[BowJunkie]

I was doing some research for other options and ran across a Field and Stream article from 1995
This may give you other options to try first.

http://books.google.com/books?id=rC543tF8Zr4C&pg=PA10&lpg=PA10&dq=arrow+flight+of+a+self+bow&source=bl&ots=E3rPky3LrC&sig=HTu8wNw6QW_JOYVX0zE7KKXbPJo&hl=en&ei=0qU-Ts_kB_CGsALjlIjEBw&sa=X&oi=book_result&ct=result&resnum=10&ved=0CFgQ6AEwCTgK#v=onepage&q=arrow%20flight%20of%20a%20self%20bow&f=false

Copy this link and paste it in your browser.
Specifically  Page 10 the last paragraph

[wvarcher]

     Bowjunkie, thanks for the link.  draw Length is measured by knocking an arrow and then having someone else mark the shaft at the back of the bow.  I get 27.5" that way.  28.5" sounds about right if i measure from the nock throat to the field point tip.  I forgot to mention that i was using arrows with a 55lb spine.

[BowJunkie]

Try tweaking the brace height first and see if it gets any better.
Keep me posted

[Pat B]

28", 45# spined arrows should shoot well from your bow.  If you leave your arrows long you can reduce the effective spine weight by 5# per inch over 28"...so arrows spined at 55# but cut to 30" will have an effective spine of 45#.

[wvarcher]

thanks guys.  dropping down to 45lb spined arrows seems to get me better flight.   my brace height is now at 6.5" inches instead of 6".