One Shaft in Another Shaft Questions

[PopeandYoung_51]

I watched the Paul Schafer Cape Buffalo video of the penetration test. He mentions putting a 1916 in a 2117. I am thinking about doing this for a bison setup.

What spine of arrow would this produce?
Would a guy just glue the inner shaft to secure it?
Does anyone know for any other arrow combinations that would work?

I was hoping to use 2013s and 1916s so I could use the 5/16 field points I already have.

Corrected Math:
So the inside diameter of the larger arrow should be close to, but greater than the outsider diameter of the smaller shaft.
IDL > ODS = Inside Diameter Large > Outside Diameter Small

Paul's set up (2117 and 1916):

IDL=ODL-Shaft Wall=(21/64)"-2*.017"=.294125"
ODS= (19/64")= .296875"

So the difference between 2117 ID and 1916 OD= IDL-ODS=.294125"-.296875"=-.00275" (Paul'setup shouldn't have worked?)

My possible set up( 2013 and 1916)
IDL=ODL- Shaft Wall= (20/64)"-2*.013"= .2865"
ODS= (19/64)"= .296875"
Difference=IDL-ODS=.2865"-.296875"= -.010375" (Won't work)


1816s:
Then, ODS (18/64")=.28125"
and Difference for 2013 and 1816= IDL-ODS= .2865"-.28125"=.00525"(Should work)

I'm very interested in calculating spine, if anyone knows how.

Just trying to avoid spending $300 on various arrows. I asked 3 Rivers and they weren't any help.

Any advice is greatly appreciated!
Thank you,
Coltin

[PopeandYoung_51]

Also, if there's something missing or wrong with my math, please point it out!

Send a PM to Buff. He has worked up arrows like this for Cape Buffalo, Asiatic Water Buffalo, and Elephant!

Bisch

[PopeandYoung_51]

Thanks Bisch!

[Fletcher]

I didn't check your math, but you do need to double the wall thickness.

You won't get a 1916 inside a 2013, but an 1816 should fit.  I haven't a clue what the spine will be.

Good luck with your bison hunt!

[Hermon]

You need to subtract two wall thicknesses for your IDL.

[JimB]

I honestly think you might be making it too difficult.As big as bison are,they don't have the same rib structure that Cape buffalo and water buffalo have.There are a lot simpler ways to build a heavy arrow these days and there are some real tough heavy weights available now,as well as tough broadheads to chose from.

At any rate,if you still want to double up some aluminums,this chart can help with the diameters,at least.
 

[PopeandYoung_51]

Thanks guys! Appreciate it!

[PopeandYoung_51]

Corrected the math, but by the numbers Paul's set up shouldn't have fit. Any thoughts?

[PopeandYoung_51]

Thanks JimB! That's exactly what I was looking for.

[Hermon]

Originally posted by PopeandYoung_51:
Corrected the math, but by the numbers Paul's set up shouldn't have fit. Any thoughts?

He inadvertently said the wrong size?  Looks like he may have meant 1816, it would fit according to those charts.