2016 spine

[Gapmaster]

I'm shooting XX75 2016 shaft at 29 inches. Can someone with a spine meter tell me what spine of wood shaft will spine out like this 2016? Thanks, Gapmaster

[Cupcake]

A 2016 is 59.3 pounds spine.  To calculate spine of aluminum or carbon divide 31.5" by the deflection listed.

For 2016: 31.5/.531= 59.3lbs.

I have verified the calculations with measurements.

[Gapmaster]

Sweet. I didn't know that math calculation. Thanks for the help. Gapmaster  

[Roadkill]

type in "arrows by kelly" and it will take you to foxfire,  look at his charts.  61# to 63# for the 2016's

[hotfootTG]

Cupcake; do you recall where the K Factor of 31.5 in your formula came from (what standard)?

I have always understood that the Factor was 26, but I cannot remember where that number came from. I'll keep looking.

Al (Als Decals)

[Cupcake]

The 31.5" comes from a derivation that converts the ATA (AMO) 26", 2#, method to the 28", 1.94#, ASTM method that is used for aluminum and carbon arrows.

When I was developing the Spine-O-Meter I used beam deflection theory to derive the conversion factor.  The result is that the deflection of a carbon or aluminum shaft measured on the wood ATA standard (26", 2#) is 0.825 x the ASTM deflection.  For a 2016: .531 x .825 = .438.  So 26/.438 = 59.3.  The more direct approach is 31.5/deflection since 26/.825 = 31.5.  I have a write-up of all of this math for anyone that gives me their email address.

[hotfootTG]

I'd like to see the math Kevin, if you would. anhharford@comcast.net.

I developed my own spine meter along with all the spine / draw weight charts using the 26" / 2# method but also a 1# set for lower weight arrows. I used a dial indicator and when loaded with light arrows, the plunger penetrated the base, thus the 1# weight.

Thanks in advance for sharing.

Al (Als Decals)

[Paul WA]

center cut bow you can do  higher

[Gapmaster]

Cupcake, does your spine-o-meter have shaft sizes (alum and wood) listed where the needle points when your spining out a shaft? Do you have these for sale? I think I need to add one to the shop.    Thanks, Gapmaster

[Cupcake]

Gapmaster,
Yes it does have the wood, aluminum and carbon all on the same scale reading.  Check the sponsor classifieds and you will find the details and photos.
Kevin

[Deadsmple]

Kevin, if at all possible, I would like to see that write up too.
vcorpus@ptd.net
thanks,Vaughn