2512 Spine
 

After reading the "Black widow spine formula" thread, I shot some 2512 Super Slams off my Hunter I. I don't know what they spine, but they flew like darts (32" long, 100 grain points). Just wondering if anyone knows the spine on these.

Chad

RE: 2512 Spine
 

Chad,
According to an old Easton chart I have: 47-62 lbs in the recurve column @ 32" long.
Darrel

RE: 2512 Spine
 

Chad, I think a 2512 at 32" with 100gr head would be just about 57-62#. They have the same approximate deflection as 2219s.

Edited by - Floxter on 01/05/2002 15:43:24

RE: 2512 Spine
 

Dynamic spin or static spine?

2215's have a static spine of about 80#. 2413's are around 90-95#. I think 2512's are in the 100# range.

JRW

RE: 2512 Spine
 

JRW, that's a dynamic spine of about #57-#62. If the shaft alone were spined on traditional 26" centers it would probably be about #95 or the same as 2219s. Easton however spines their shafts on 28" centers I'm pretty sure. Had this pointed out to me recently and it explains why I could never get the Easton charts to work with a traditional bow.

Jack

Edited by - Floxter on 01/06/2002 21:59:36

RE: 2512 Spine
 

I guess I should expand on my earlier post. According to the Easton chart I'm looking at, a 2512 @ 32", with a 100 gr point, is the preferred selection for three draw weight ranges for a recurve. They are: 47-52,52-57, and 57-62 lb. As we all know these are starting points, not written in stone, with many factors contributing. And Chad, this is probably a lot more than you wanted to know.
Darrel

RE: 2512 Spine
 

I dont have the deflection for the 2512 but I do have them for the 2215's and the 2413's

2215 deflection is .343 76lb spine
2413 deflection is .305 87-88lb spine

there is a formula to figure the deflections out...got it stuck on the tip of my tounge..will post it when I can spit it out <img src=icon_smile_wink.gif border=0 align=middle>!

RE: 2512 Spine
 

brain fart, the formula is something else....it is for deflections but for woodies and spines OOPS <img src=icon_smile_big.gif border=0 align=middle>!

RE: 2512 Spine
 

Thanks guys--I was actually looking for the spine as compared to wooden arrows (static?)

Chad

RE: 2512 Spine
 

hey Chad, bet ya Troy gag gag Breeding has it. I have a list but I dont have a 2512 on there.

RE: 2512 Spine
 

O.K. Chad, here goes. Please bear with me 'cause this gets a little complicated. Perhaps JRW or some of the others could explain it a little better. Static spine refers to the arrow while suspended between two points with a weight in the middle. Wood arrows are traditionally spined over 26&quot; centers with a 2# weight suspended in the middle and the amount the arrow deflects or bends in the middle (deflection) is measured to determine spine. On the other hand, metal arrows are spined over 28&quot; centers with a 1.94# weight suspended in the middle. So really you are comparing apples to oranges if you only look at static spine. Dynamic spine refers to the way the arrow actually flexes under stress, i.e. the way it operates when shot from a bow. Thus when we say a 2512 has a dynamic spine of 57#-62#, we are really saying that it flexes the way a #57-62# wood arrow would if shot from the same bow, even tho if it were spined on the same 26&quot; centers as a wood arrow it would measure a deflection equal to a 95# woody. With a center shot bow (one cut exactly to the center of the riser) or true center shot bow (one cut 1/2 the diameter of the arrow past center) you can use a considerably stiffer arrow than in a longbow which is typically cut 1/8&quot; before center. For this same reason compound shooters can use extremely stiff arrows with light point weights compared to comparable poundage traditional bows. So while the static spine of your 2512s may be #95 when measured on 26&quot; centers like your woodies, it is not unreasonable to see them act like 57#-62# woodies when cut to 32&quot;. Remember, for every 2&quot; of draw over 28&quot; you need to increase aluminum arrows by one size (5#) or 10# in your case.

Jack

Edited by - Floxter on 01/06/2002 22:00:51

RE: 2512 Spine
 

Thanks Jack--you explained it perfectly. I knew a good bit of it, but didn't know what static and dynamic spines were. Have just wondered why a bow that would shoot a 150# (static) spined aluminum would also shoot a 80-85# wood.

What are your opinions on going way heavy on spine with centershot bows? Any advantage to it? I can shoot my 105-110# spine cedars on a recurve I have, but it also shoots 75-80# and 80-85# just fine (to my eye--haven't paper tuned).

Chad

RE: 2512 Spine
 

Actually, the static spine numbers that I was refering to were done by people with spine testers on the LW and measured with the standard 2# weight hung in the middle of the shaft suspended by points 26&quot; apart.

Jack, I think you're right, it should spine the same as a 2419.

Dynamic spine is how an arrow &quot;reacts&quot;. For every 1&quot; difference in length, or 35 grain difference in point weight, they arrow will &quot;act&quot; 5# heavier or lighter. For example, if a 32&quot; 70# spine POC with a 125 grain tip will shoot well, so will a 31&quot; 65# spine with a 125 grain tip, or a 32&quot; 75# spine with a 160 grain tip.

JRW

RE: 2512 Spine
 

Chad, I don't really think there is any advantage to shooting overspined arrows other than it might allow you to interchange different bows with the same arrow or allow you to shoot a heavier arrow. However, you can accomplish the goal of heavier arrows thru other means, such as point weight or shaft material. Using an overly spined arrow will reduce the forgiveness of the arrow and accuracy will suffer unless you have a perfect release every time. That's why I feel bare shaft testing is so valuable. It will show that while different spines will all shoot out of the same bow, one particular spine will be consistently more accurate in terms of right and lefts (windage) than the others and will allow for an occasional imperfect release. For this reason I don't papertune, because I've found that while I can shoot bullet holes thru paper, if my release is slightly off it will give me an tear rather than a bullet hole, even tho the arrow will impact to point of aim. Thus I don't think papertuning is a reliable method of tuning with fingers off the shelf. Just my opinion. Others may feel differently.

Jack

RE: 2512 Spine
 

Y'all think Easton uses different centers to throw a monkey wrench in the works? I've always wondered why static spine was calculated (mainly) using 26&quot; centers & draw weight on &quot;off the shelf&quot; tradbows used 28&quot; as standard. Easton using 29&quot; centers & AMO using a 30&quot; draw only complicates matters further. If everyone was on the same page this would all be much simpler, but obviously that ain't about to happen. Go figure, huh?

RE: 2512 Spine
 

Arrowsmit, I don't mean to be picky, but AMO uses 28&quot; as the standard for measuring draw weight. Actually, they measure draw at 26.25&quot; to the pivot point of the riser and then add 1.75&quot; for arrow clearance to the back of the riser for a total of 28&quot;. But you're sooo right; why not one measurement for everything, whether 26&quot;, 28&quot;, or 30&quot;???

Jack

Edited by - Floxter on 01/06/2002 22:02:33

RE: 2512 Spine
 

Hmmm, my bad. I thought AMO rating had been &quot;standardized&quot; as 60# @ 30&quot;/540 gr arrow?

Jeez, this is way overcomplicated.

RE: 2512 Spine
 

Arrowsmit, you are right! That is the way AMO measures to determine arrow speed. However, to measure draw weight they use the 28&quot;. Just another of the inconsistencies you pointed out.

Jack

RE: 2512 Spine
 

Huh? I'm RIGHT?? Hmmm...you sure about that? <img src=icon_smile_big.gif border=0 align=middle> Hehe. Didn't Bowhunting Worlds technical editor, engineer Norb Mullaney (sp) come up w/that index in the late 70's/early 80's? Heck WHO KNOWS??? Oouuw, my heads a hurt'n. <img src=icon_smile_wink.gif border=0 align=middle>

Edited by - Arrowsmit on 01/06/2002 14:03:20

RE: 2512 Spine
 

dang guys..and they say this trad crap is easy! <img src=icon_smile_big.gif border=0 align=middle>!

RE: 2512 Spine
 

If it flys well and hits where you aim, who cares about what the spine is? I guess I have a very simplistic attitude toward these things. Dick