I'm shooting a Morrison Cheyenne, 63#@31" & I need to build a few wooden arrows (pig hunt, dogs involved, need snappable shafts)

I have absolutely no idea what spine shafts I need. I have broadheads in all weights from 125gn up to 200, so that's not an issue.

Can anyone point me in the right direction spine-wise please?

with that draw I would go with 85-90 / 90-95

Might be hard to find them... try some of the sponsors

I've got a half dozen kicking around that are 85/90 I believe. Thanks Sal!

play with point weight

My 58# longbow shoots 60-65 spine ash shafts with 125 zwickeys up front quite well.

Good hunting..

MM

Mike what's Your draw length? Rob has a 31"draw.

Okay.

Actual draw weight plus five: 63 + 5 = 68.

Plus five for each inch of arrow length over 28" (I'm going to assume an inch of overhang at the front of the bow): 68 + 5 + 5 + 5 + 5 = 88.

If bow is cut to or past centre, plus five: 88 + 5 = 93.

If using a modern, low-stretch string, plus five: 93 + 5 = 98.

Add nothing for 125 grain or 145 grain broadheads. Add five for 160 grain broadheads. Add ten for 200 grain broadheads.

So, if using 125 to 145 grain heads, as 98 is closer to 100, and I believe it better to err on the side of stiffness than weakness, you would choose 100/105# shafts. If using 160 grain heads, you would choose 105/110# shafts. If using 200 grain heads, you would choose, theoretically, 110/115# shafts. However, as your need for spine increases, something pretty cool happens: The difference in actual deflection becomes so little that a wider range of shafts will work. So, you would find that you really won't go wrong with anything over 105#.

As an example of my belief that it is hard for arrows to be too stiff (given a reasonably heavy bow cut to or past centre), I should be shooting 95/100# shafts out of my ~68/69# @ 29" recurves, and I do, but I also can happily shoot 105/110# shafts intended for my much heavier recurve, and they still fly beautifully and kill magnificently.

Now, Surewood Shafts are really the only place to get what I described above.

Good hunting!

Hey Rob, I ran the numbers thru my system and came up with 97 lb for a 31" BOP and 125 point.  Stu's Calc said 103 lb for a parallel shaft, but the calc always runs a little high for me.  If you keep the point taper to 3/4", you should be able to get 31 1/2" BOP from a 32" full length shaft.  Longer will require a foot.  The Reparrows work well for this.  I'll agree with Ben that you will be better to err on the stiff side, esp with a deep cut shelf.  Surewood will have the heavy spines.  Let me know if I can help.

Rob,

My brother-in-law is a foreman for our local telephone company. I'll ask him if they have any old or spare posts the could spare. Good luck on your upcoming hunt.

Aloha,
Kawika

I have a 55@28 52" kodiak magnum that I overdraw to about 30 inches. My 60-65# full length ash shafts tipped with 125gr broadheads fly very well for me.  :D

Depends on many things.  I draw 30" and have a 52#@28" bow that shoots 60-65# spine cedar just beautifully (cut to 30-1/2" BOP) but a 55#@28" bow that needs a 65-70# spine; all with 125 gr heads/points.  

There is a lot of forgiveness (or at least you can tune the bow some).  I have bows of seven different draw weights from 43 to 60#@28", all 2# to 5# apart, but I only keep three spine ranges of cedars: 55-60, 60-65 and 65-70.  I do a lot of playing with "shaving" the rug or leather pad on the riser and with nock point and brace height until I get the bow tuned to one of those spines.  My Martin/Howatt and Browning both are very tolerant (and cut to center) and I can shoot 60-65 & 65-70 with 125 gr heads.

Uncle Robbie, pick up the phone and give fletcher a call for some 100+ spine Surewood shafts and you will be good to go.

Rob, the Morrison is cut well past center, and if you draw 31 you will need a 33 in shaft to give you an inch of clearance between fingers and broadhead. You need 33" to make a 32" arrow. 32 is about max when it comes to shaft length. Surewood may be able to supply 100/105# shafting in your length, or get Fletcher to foot some for you. Have a great hunt!

I'd be rummaging through the dowel barrel at Lowes for 3/8" birch at that point.  Amazing that 4# added weight and 1" added draw would need 30# more spine.  ;-)  (The bow should already have 1-3/4" beyond the deepest part of the grip factored in if it is marked 63#@31" - I only need to add 1/2" . . . not 2")

So far ,when it comes to these issues Bjorns the man.Good job sir!

You lose about 1" with the point taper, so a 32" shaft will give you about a 31" BOP arrow.  The nock can give you another 1/4" and if you only point taper 3/4" you can get about 31.5" BOP, but that is about the limit.  I have some 34" fir, but they aren't stiff enuf for Rob.  Rob's Morrison is cut well past center, about 3/16"; that is where much of the additional spine need comes from.

Rob could build the shelf out a bit to shoot a lower spine, but that would mess with his regular arrows.