I know you guys are sick of spine questions, but............

[dan d]

I think I'm too stiff of spine for my old Bear supermag, some charts say yes some say no. It is confusing stuff if you really roll up your sleaves and start over thinking it like I have been    

I use an iPad so Stu's calculator don't work for me so here's the specs.  1970 Bear supermag, 45 pounds @ 28, I pull 26.5 inches, use standard 28 inch cedar arrows with 125 grain heads.

I use a tab, the bow has fat B-50 string.

Hmmm........  I think that's it for info needed, I would like to hear both schools of thought, those who are calculator / engineering type & those who know from experience.

Thanks,
Dan

[inthere10x]

This is the older version of Stu's calculator, which I use on a iPad.

 http://www.3riversarchery.com/spinecalculator.asp

[LB_hntr]

Charts and calculators are great to get you started. But many factors come into play such as your release, if the bow is actually the weight it says (many bows are a few pounds either side and some loose weight over time if left strung, etc), and other factors. Your best bet is to use the charts and calculators to get "in the ball park" buy 3 shafts in that range, 3 stiffer, and 3 weaker. Then you can experiment with weights, heads, etc and find what works best for you. Dont even fletch them. Shoot them bar shaft and se what they tell you. There really is no substitution for seat of the pants testing when it comes to arrows. Yes, you can get what the chart says and make length, and weight adjustments to mkae them work. but best bet to really get what you want and have it your way is to do the testing. it sucks to spend the money for test shafts. But once you have the testing done you can buy with confidence and know you have the absolute best set up for you.

[dan d]

What is this gobbley gook on stu's chart:
    -For Wood or Other, enter AMO static spine
      (2# @ 26") (enter exact poundage, for 60# use 60)   static spine  
    -For Wood/Other, enter shaft grains per inch (GPI)

I use good ole 11/32 cedar shafts cut to 28 inches, what the heck is static spine ? If I knew the spine I wouldn't be asking the question !

I imagine GPI is taking the total weight of my arrow & deviding it by 28 to get my grains per inch ?

I just had a friend call & says on page 66 of three rivers catalog the chart says I should be between 35-40 spine, I have seen charts say 50-55 spine. I guess LB Hntr is correct & I need to buy 2 test kits to cover the bases, if I remember right that will be a $40 experiment, that does not bother me as bad as hunting season is only a month or so away & by the time I do the experiment to find what I need & then get what I need ordered it will be hunting season !

I guess I screwed up waiting this late in the season to find out the reason I'm not grouping (usually hitting to the left) is that I'm overspined, I'm shooting arrows that are right at a 55 spine.

Was just looking for a quick fix verses a 2 week one, as hunting season is coming soon.

Thanks,
Dan

[LB_hntr]

a quick fix and maybe one that you like best of all is to add more weight to the front of the arrow to decreas the spine. think of it like this. if you put the insert end of the shaft against a 10 pound object and you push the nock end of the shaft with your hand at the point that the 10 pound object moves the shaft will be flexed a certain degree. if you increas that 10 pound object to a 15 pound object and then push on that the shat will flex more at the point the 15 pound object moves.
Same principle with front end weight. the more you have weaker the spine gets. when the string pushes the nock end of the arrow the weight in the front of the shaft helps determin the amount of arrow flex.
so if you arrows are overspined and you add a 100 grain steel broadhead adaptor, or a 100 grain bras instert, or heavier head, etc. you will decrease the spine of the arrow.
Might, and I say might solve your problem, but testing with bare shafts is the best way to know.

[dan d]

Thanks for your thoughts LBHntr, I was thinking of ordering arrows at 45-50 spine & not having the length cut & I could play around with lentgh verses point weight as I only have 125 points / hunting blades laying around. But basically playing with length is doing the same thing.

I think I'm way over at 55 spine as some chart says I should be in the low 40's.

[Bladepeek]

If i recall, you had a post sometime back and the consensus of opinion was that your were overspined.

I think picking up some varying weights of field points and finding out what you need up front would be a lot cheaper and quicker than buying new shafts at this point. You could probably go all the way from 125 gr up to over 200 gr for very little money. Then get a pack of broadheads of that weight and you would be very, very close. At much closer than it sounds like you are now.

[SAVIOUR68]

IMO dan you are way over spined and I believe that you should need around low 40's also, leave them full length and cut them slowly til you find the sweet spot.

[dan d]

Originally posted by Bladepeek:
If i recall, you had a post sometime back and the consensus of opinion was that your were overspined.
.

Bladepeek, you are correct on that post, but..........  The census was not clear, one member said 50-55 & another agreed,  I was leaning heavy on the fact that I was overspined but I will admit I can google & find charts that say anywhere between 40-45 to 50-55. That's why I posted this is confusing stuff. There is a lot of difference between 40 to 55 if I go to extremes on what the charts show.

I guess I was hoping to find someone say I shot the same setup as you Dan & I use -- spine.  

I'm gonna order a test kit as that seems to be the correct way to go, just didn't want to spend the 2 weeks experimenting (1 week to get & try the test & another week to get correct arrows)  

With only 5 weeks before hunting season.

Thanks for the advice guys !
Dan

[xtrema312]

If you are planning new wood arrows, I would get with one of the great arrow builders on this site and have them set you up.  They should be able to get you real close.  They a little cutting and testing should get you fixed up.  They can also probably provide you with a bare shaft and even a couple different point weights so you can experiment a little bit too fine tune.  

Carbons take a bit of fussing with due to the limited spine selections and the way they act, but wood should not be that hard to work out.