Author Topic: Spine deflection chart (Read 1005 times)

KentuckyTJ · « **on:** March 24, 2009, 02:59:00 PM »

Does anyone have a chart showing all the deflection #'s of all the shafts?

aromakr · « **Reply #1 on:** March 24, 2009, 06:15:00 PM »

If your talking about wooden shafts, its a simple formula 26 divided by the deflection = pounds of bow weight i.e. 26 divided by .520= 50# and visa-versa 26 divided by pounds= deflection.
Bob

Kevin L. · « **Reply #2 on:** March 24, 2009, 06:56:00 PM »

Let me look around, I used to have one somewhere on this danged box.

reddogge · « **Reply #3 on:** March 24, 2009, 07:02:00 PM »

Is this what you wanted?
web page

KentuckyTJ · « **Reply #4 on:** March 24, 2009, 07:23:00 PM »

No what I am looking for is a chart that would show deflection of a Easton Legacy 2016 so I can cross reference to know which carbons to buy. I'm pretty sure it's .500 but not positive.

Sorry I didn't explain my question better.

George D. Stout · « **Reply #5 on:** March 24, 2009, 07:25:00 PM »

Well he said "all the shafts" so I'm assuming he means all the shafts 8^). That web page is for wood which is spined at 26". Aluminum and carbon are spined at 28" so a .520 at 28" span will be stiffer than a .520 at 26".

KentuckyTJ · « **Reply #6 on:** March 24, 2009, 07:34:00 PM »

Well I only am needing aluminum and carbon but If I were making the chart I would include "ALL" shafts including wood.

George so do you know of any chart for this?

vermonster13 · « **Reply #7 on:** March 24, 2009, 07:37:00 PM »

2016 = .531 deflection @ 28"

Hot Hap · « **Reply #8 on:** March 25, 2009, 01:22:00 AM »

1716=.880
1816=.756
1913=.733
1916=.623
2013=.610
2016=.531
2018=.464
2020=.426
2114=.510
2115=.461
2117=.407
2213=.458
2215=.419
2216=.376
2219=.337
2314=.391
2315=.342
2317=.297
2413=.365
2419=.268

I think that these are the ones that are most in use. I have other figures if you have a different shaft.

Hap

KentuckyTJ · « **Reply #9 on:** March 25, 2009, 11:38:00 AM »

Thanks HH. thats perfect I'll cut and paste that beautiful info into an excel file.

George D. Stout · « **Reply #10 on:** March 25, 2009, 12:19:00 PM »

You may find this useful for figuring spine/weight.

http://www.jvd.nl/catalog/pag103.pdf

KentuckyTJ · « **Reply #11 on:** March 25, 2009, 01:55:00 PM »

Great George thanks. I wish these 3-rivers Traditional only carbons/Easton ICS shafts where on this chart but I can figure it out from here.

Thanks T.J.

vermonster13 · « **Reply #12 on:** March 25, 2009, 01:56:00 PM »

They don't need to be. Their number is their deflection 500 = .500 400 = .400 for the carbons.

KentuckyTJ · « **Reply #13 on:** March 25, 2009, 02:01:00 PM »

Duh, thanks David. Just so I'll know the answer if it ever pops up in our trivial pursuit game. How much weight is hung from the shaft to do the deflection testing?

vermonster13 · « **Reply #14 on:** March 25, 2009, 02:11:00 PM »

wtpops · « **Reply #15 on:** March 25, 2009, 02:38:00 PM »

Quote

Originally posted by KentuckyTJ:
Duh, thanks David. Just so I'll know the answer if it ever pops up in our trivial pursuit game. How much weight is hung from the shaft to do the deflection testing?

Correct me if im wrong but for most wood it is 2# @ 26" and for most aluminum and carbon it is 1.94# @ 28"

vermonster13 · « **Reply #16 on:** March 25, 2009, 02:40:00 PM »

AMO is 2# at 26" (yes most wood is done that way). All the main stream manufacturers do it at 28" for what ever reason.

dino · « **Reply #17 on:** March 25, 2009, 08:18:00 PM »

Easton/ATA deflection is measured on 28" centers with a 1.94 weight. Old AMO/Trad shafts are measured at 26" centers with a 2# weight. The story is that an employee at Easton put their spine tester weight on a scale one day and seen that it was 1.94lbs, so that became their standard. Don't know how true it is, but sounds like a good story.

On the same note the new Ace spine tester is a convertable spine tester that it can measure both the 26" center with the 2# weight and then convert to a 28" spine tester with a 1.94# weight. A finely designed piece of equipment that works really when I worked with it last.

tecum-tha · « **Reply #18 on:** March 26, 2009, 08:53:00 AM »

If you know simple statics, it is easy to calculate different measured static spines.

If you want to measure stiff spines exaxtly, you need to go up in either distance or in weight or both to get a greater deflection. Greater deflection will be less prone to measurement errors. The AMO Spine chart is ok until 80#, then it is not really accurate anymore.
It is perfect in the 30-50# range.

Old York · « **Reply #19 on:** March 26, 2009, 11:21:00 AM »

Maybe this is why Easton went to 28" & 1.94#, to deal with the really high spines with carbons & compound bows?


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Author Topic: Spine deflection chart (Read 1005 times)

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