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Main Boards => PowWow => Topic started by: SveinD on February 10, 2010, 05:23:00 AM
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Does anyone have a link or know what values to insert for wood types/spines?
The only info I have gotten so far is 12,2grains per inch for 45-50# 11/32 POC, and I don't even know if it is correct..
It would be nice if it was added to the next version of the Calc :p
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Don't know about a calculator, but that 12.2 gpi would change from group of arrows to group of arrows. Hap
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GPI on wood shaft is a big variable. Type of wood, well seasoned or not, and density. If you have shafts you just have to calculate the GPI yourself and plug it into the Calculator.
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Here is what stu miller had to say, when I asked about wood arrows...
"First, go ahead and plug in the fixed variables that you know about the arrow.
Then select "wood shaft" from the arrow size drop down menu and also enter your nock weight (I use 13.5 for a Bohning Classic nock)
No comes the fun part! The two boxes below the "wood shaft" selection are the two variables you can play with, static spine and GPI. First figure out what type of wood shaft and GPI youwill be using.
I use 11.1 for Sitka Spruce, 12.2 for POC, and 13.5 for Douglas Fir as examples. It is best to measure your actual raw shaft weights as we all know wood varies a lot. From there just enter a static spine number until the dynamic output number for the arrow matches your bow's requirement."
hope this helps,
sammy
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Thanks for the replies :)