Sorting Spine

[dan76]

Ok so I have been shooting a batch of arrows out of my recurve for a while now but haven't been completely happy with them, so long story short after exhaustive paper tuning I have arrow X that is just right only problem is it is 1 and a half inches shorter than I want and 45 grains too light in the tip than I want. It seems my bow and my shooting style meens I need a fairly stiff arrow but I like to shoot a heavier point and I need the lengh to clear a broad head in front of the riser. So my question is if I want to add that length and add that weight to the point how many pounds up in spine should I go to be able to do that.

Thanks Dan

[longbow steve]

Hi Dan, I dont think paper tuning is the best option for a finger release unless you are sure your release is as good as it can get. If anything the bareshaft method I have found to be most effective. Are you using timbers , alloys or carbon? Alloys are a good shaft to use when determining what set up you want as they come in a broader range of spine and then can be replicated in your timbers. Give us a run down of what you have found to be best suited and also you bow draw specs, brand, string type etc. Steve

[dan76]

Ok i shoot a 60" Great Plains one piece recurve(the one with the bamboo limbs) 50# at 28 i draw 29" to the throat of the grip, i only shoot wood shafts, sitka spruce from hildebrand i think thats how you spell it. I shoot off a brush rest at the moment, three under, fast flight string. Im sorry but i got to say that i don't agree about the bare shafting, a poor release will show up through paper or bare shaft just the same, but that being said i don't shoot one arrow then make adjustments i shoot the same arrow a minimum 5 times through the paper to make sure of the result and if my release is bad then it is consistantly so. I have found that bare shafting shows the same results as paper just magnified and paper is a good place to start. I have been shooting the same spined arrows for quite a while and always had a weak spine reaction but it has gotten a little worse since going to 3 under so i decided to knuckle down and get it right, i will be getting some test shafts from srub bull shortly but i want to know the best place to begin. Can you get consistant false readings of weak spine from overlly stiff shafts. The shaft i am using now for testing is a 60-64 at 26 shaft and to get close to what i think is right i had to go to a 100 grain tip 3 4" fletchs arrow length nock throat to the back of the head is 27.5" and that is pretty good not perfect but i can't physical shoot any shorter.
oh and i have a cricket clicker on my bow as a draw check.
Dan

[dan76]

Could i be getting tail slap of the riser giveing me a false weak reading.
Dan

[Stickbow Hunter]

So your draw would be approx 30" to the back of the bow and allowing an inch for clearing your finger with broadheads you would probably want shafts 30.5 - 31" to the back of the head? At around 30" draw you would be drawing approx 55#. I would suggest the following but I have never paper tuned of bare shaft tuned as I have never found the need to.

I would firstly cut your shafts at the lengths you want them and fit the weight head you want to use. I would get a range of spines and test them to see which ones shoot correctly.

I would suggest starting with 70 - 75# spine.

I would also use three by 5" feathers as opposed to 4" ones.

If you are using three under check your nocking point is high enough as often you have to raise it for three under if the bow wasn't tillered for it.

Check your brace height also.

All the best with it.

Jeff

[dan76]

Yeh thanks jeff, Hey steve in the interests of science i just went down while it wasn't raining and stripped the feathers off 3 arrows and changed points to 100 145 190 grain all arrows shot nock left and impacted to right of center the worst being the 190 each shaft was shot 10 times in groups of three. Jeff you helped me make my first set of arrows and we just did it the you always do and they where great for my longbow but this recurve is a different animal altogether and is a bit picky about what you feed it Is it common to have to run arrows so over spined like that. I have some easton power flight carbons here too in the 500 spine and i tested them and they are under spined as well and with the irrigation tube up the guts and 145s up the front they fly pretty good but they could be better.

Dan

[Stickbow Hunter]

Is it common to have to run arrows so over spined like that.

It is for me.

Using my calculations above (that you are drawing around 30" so your bow will be about 55# draw weight) you need to go up a couple of spine groups for the extra two inches of draw above 28" so that would make them 65 - 70# at least. Anyway try a few different spine groups and see which fly correctly.

As I also said above, I think it best to keep all the shafts at the length you want them and with the weight head you want; just vary the spine weights.

Jeff

[slvrslngr]

Dan-I'm not following your description of your draw length. You said you're drawing 29" but your arrows are 27.5 boh, so are your arrows barely sitting on the shelf? I'd check your draw length again to make sure we're all on the same page. The easiest way to do it by yourself is to nock an arrow, mark it where the front of the riser (the edge of the riser furthest away from you) and the arrow meet. Then put a clothes peg on the arrow and draw the bow to full draw, keep in mind you will have to let the clothes peg hit the front of the riser and slide along the shaft. Carefully let down and measure from the throat of the nock to the clothes peg, do this 3 times and take the average, this will give you your actual draw length. Without knowing for sure what your actual draw length is, we can only guess as to what spine shaft you'll need.

Just for reference, my draw is 29.5", I'm shooting doug fir arrows at 31" bop, spined 65-70, with 160 grn. field points, this is out of my Flatline recurve which is 55#@28", so my actual draw weight is about 59#'s. They seem to be a touch weak, but are flying good. I need to put some broad heads on and see how they go, that will be the real test.

(Edited to change how to measure the arrow. )