arrow length vs arrow spine

[carpenter374]

Hey all. i was thinking about arrow length and arrowhead weight vs arrow spine. i thought it might be feasable to adjust the length of arrows to make them spine heavier with a shorter arrow or lighter with a longer arrow and/or heavier point. i tried it and it seems to work. i used 10 ramin wood dowels and glued home made tips on. i left the arrows longer at first and adjusted them all until they all shot consistently. i ended up with 9 the same length and the other a half inch longer. one arrow has 125 grain point the rest are 145.
they all consistency match well. just an idea vs throwing away good shafts that dont spine the same as what you shoot. let me know what you guys think. 

[Justin Snyder]

Arrow spine is calculated by deflection of 28" arrow. It is well known that adding 1 inch will decrease spine by about 5# and subtracting 1" will increase by about 5#.  A 31" arrow that reads 55# on a spine tester would have an effective spine around 40#.  Also adding the weight up front to the tip will decrease the spine.  Justin

[John K]

Justin did you mean subtracting 1" will increase by about 5#'s 

[Justin Snyder]

Justin did you mean subtracting 1" will increase by about 5#'s 

Of course I did, isn't that what you thought when you read it.  If that is the worst mistake I make today Ill be a happy man.  Thanks for fixing me before I really confused somebody. Justin