UnderSpined Arrows

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InnerEvil
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Joined: Tue Dec 23, 2014 8:04 pm

UnderSpined Arrows

#1 Post by InnerEvil » Mon Jan 05, 2015 9:41 pm

Hi guys, im a new archer, i recently bought my self a 2nd hand #35 samick sage got myself 12 arrows
(1535 gold tip traditionals) and was away, 2months and proberly 2000 arrows later my bottom limb has cracked was only my 2nd arrow of the day, now i have a 2nd set of limbs but they are #50 my question is will i be able to shoot my current arrows safely or am i going to have to buy a new set will they be too underspined?

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Mick Smith
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Re: UnderSpined Arrows

#2 Post by Mick Smith » Tue Jan 06, 2015 7:25 am

Welcome to the site. :smile:

I'm pretty certain you will need another set of arrows, as 50lb is quite a bit heavier than 35lb and that's the maximum draw weight your current arrows are spined for. If your draw length is close to 28 inches and if you're using 125g points and if you want to stick with your current brand of shafts, then you will need to buy some 35-55 spined shafts/arrows.

You haven't mentioned your draw length. It is relevant in this scenario, as the quoted official spines only relate to a draw length of 28 inches. If you have a longer or a shorter draw length, you must compensate, for example, if your draw length is 26 inches you may get away with shooting 15-35 spined arrows from a 50lb bow.

Arrow spine isn't usually an exact science, in that it's totally predicable under all circumstances. It's more of a 'suck it and see' type of scenario, where you might try a couple of combinations before you finally get it right.

Generally speaking, if your arrows behave erratically and/or group largely well to the right of the target (if you're right handed that is), then you can safely assume your arrows are under spined.
There is no use focusing on aiming if you don't execute the shot well enough to hit what your are aiming at.

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perry
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Re: UnderSpined Arrows

#3 Post by perry » Tue Jan 06, 2015 7:53 am

I would not shoot those Arrows, you might find yourself with Carbon Splinters in your Forearm, please don't risk it ! Are you a member of a Club where an experienced Archer may be able to advise you ? With a few more details like Draw Length, type of Shooting, ie Field Archery, FITA Target etc so we can make a recommendation for a starting Point

regards Jacko
"To my deep morticication my father once said to me, 'You care for nothing but shooting, dogs and rat catching, and you will be a disgrace to yourself and all your family.' "

- Charles Darwin

InnerEvil
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Re: UnderSpined Arrows

#4 Post by InnerEvil » Tue Jan 06, 2015 3:22 pm

My draw length is 27.5 inches, I am a member of a club, i have my first 3d shoot this weekend but if its not safe to shoot my arrows ill just have to get another set of arrows:( the cost of replacement limbs is almost the price of a new bow:( might just have to suck it up and buy a new one.

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Mick Smith
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Re: UnderSpined Arrows

#5 Post by Mick Smith » Tue Jan 06, 2015 4:18 pm

Are you talking about the Ballarat trad shoot this weekend? If so and if you're really stuck, I can lend or sell you some good timber arrows that are spined for 50#. For all intents and purposes, they will shoot as well as 35-55 Traditionals. They won't be as strong though.
There is no use focusing on aiming if you don't execute the shot well enough to hit what your are aiming at.

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perry
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Re: UnderSpined Arrows

#6 Post by perry » Tue Jan 06, 2015 5:33 pm

A Bow is the cheap part of this Game, Arrows, are expensive and you will break or loose them, goes with the Territory. In time I hope you choose to learn to make your own Timber Arrows from Scratch. There is plenty of Folks about to Teach you or info online so it will save you Cash but cost you Time. Well invested in my view.

IMO for a beginner it is hard to go part the economy, durability and convenience of Carbon Arrows. Sadly buying Archery Gear in Australia is expensive and often available at 1/3 the Cost Oversea's, trouble is if we don't support our local Dealers we won't have them.

Bite the Bullet, buy some new Arrows for this Bow, lighter Limbs are also a good idea just because :wink: Micks offer is most convenient provided they Shoot well. I'd guess with you Draw and a 50# @28" Bow you might be drawing about 47# its a reasonable guess a set of 29" 500 Spine Carbons, 30 grain Alloy Inserts and 125 gr Field Points would Shoot. The 125 gr Points and light Alloy insert may give the option of switching to Heavier or Lighter Points to match Spine a little closer. With 46# ILF Bow and 28" Draw I use 500's cut to 29.5" 50 grain Brass inserts and 125 gr Field Points, Arrows weigh about 480 grains. If possible try before you Buy.

regards Jacko
"To my deep morticication my father once said to me, 'You care for nothing but shooting, dogs and rat catching, and you will be a disgrace to yourself and all your family.' "

- Charles Darwin

Dennis La Varenne
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Re: UnderSpined Arrows

#7 Post by Dennis La Varenne » Wed Jan 14, 2015 12:51 am

First up, like everybody else before, I too reckon you will need stiffer arrows.

However, I would first suggest that, because you are shooting syntharrows, they are not too likely to shatter if you do have a shot with one of them from your new bow and actually see what happens.

If they come out like darts, no matter where they strike, they are shooting OK. Hitting your mark is then a matter of aim adjustment.

If they fly erratically - demonstrating an obvious wobbling side to side (fishtailing) or any other kind of wobble, then they are too weak for the thrust of your bowstring against the arrow which causes the arrows to buckle as they leave the bow.

If this occurs, it proves you need stiffer arrows.
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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perry
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Re: UnderSpined Arrows

#8 Post by perry » Wed Jan 14, 2015 9:52 pm

I know Dennis's advice was given in good faith - Don't Shoot them Please InnerEvil, they are underspined, you don't need to Prove this - Every manufacturers Spine Chart will indicate this, my experience supports this as will this very handy Tool - http://www.heilakka.com/stumiller/

regards Perry
"To my deep morticication my father once said to me, 'You care for nothing but shooting, dogs and rat catching, and you will be a disgrace to yourself and all your family.' "

- Charles Darwin

Dennis La Varenne
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Re: UnderSpined Arrows

#9 Post by Dennis La Varenne » Thu Jan 15, 2015 3:54 am

Interesting how Perry and I can have two completely different experiences doing the same thing. I have done and still shoot 30lb spined wood arrows from my 40 - 45lb bows with no problems at all. So what is it we do differently?

CORRECTION TO ABOVE - MY ARROWS ARE SPINED 35LBS - AVERAGE OF 0.750" DEFLECTION, NOT 30 LBS.
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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Kendaric
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Re: UnderSpined Arrows

#10 Post by Kendaric » Thu Jan 15, 2015 4:56 pm

I have found that for approximately every 1/8" outside centreshoot on the bow, the arrow requires about 5# less spine (all things being equal). I have also found that a longbow (as opposed to modern longbow [semi recurve] or a recurve) you need to drop another 5# off the end spine. A self bow, 10#.

Fishtailing - if a spine issue, can be caused by two things, an arrow well underspined, but also an arrow that is overspined (the rear end of the arrow, because it is so stiff, hits the window on the way out and causes a deflection, which you see as a wobble.

This is were I have found the Stu Miller spine chart on 3 rivers to be invaluable: http://www.3riversarchery.com/SpineCalc ... asp?pass=2

But having said all that, I cant help feel that shooting well underspined carbon arrows a bit of a concern.

I note that the 1535 Gold Tip Traditionals you mensioned appear to have a spine of .600". By varying the arrow length and point weight (options are 75 - 150gr) you should be able to achieve an accepable tune, depending on your drawlength and the Samicks centreshot measurement.

Whilst the aforementioned chart does not have those particular arrows mentioned, when substituted with other shafts that appear to have a 600 spine, based on a 28" arrow and 125gr point, we appear to get an arrow dynamic spine between 55-62#. A Samick Sage, at 50#, with a 27" draw, using B50, has a dynamic spine of 53.9#.

I'd say that those arrows may have been well overspined on a 35# bow. Because we don't know your exact set up of your arrows, and your drawlength, it is hard to say. The Samick Sage is not centreshot, but it is cut too centre.

Dennis La Varenne
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Location: Tocumwal, NSW. Australia

Re: UnderSpined Arrows

#11 Post by Dennis La Varenne » Thu Jan 15, 2015 9:07 pm

Kendaric,

I have found pretty much the same over the years by trial and error and apart from the few modern shelfed flat longbows I own, all the rest in my collection do not have shelves cut into them. They are very often over 1/2" out of centreshot and require very underspined arrows to bend around the handle enough. With a bow having a deep shelf, the columnar load on the arrow should produce less flexing and consequently less likely to break as a result.

This raises the question of why would it be dangerous to use arrows from 10 to 15lbs underspine safely in a bow which is 1/2" or greater from centreshot but be unsafe in a bow with a deep arrowshelf.

However, Innerevil should err on the side of caution if he has not had much experience and that is a sensible thing.

If I were in his shoes and with my present experience, I would still try the arrows out just the same. Using caution, you could still under-draw the arrows by an inch or three and see what happens and that would be a fair indicator of potential problems at a longer draw.

I honestly cannot say I have ever broken an underspined arrow from a bow, and I use only wood arrows. It has been perhaps 25 years since I last used syntharrows that I can recall. Seriously underspined arrows fishtailed badly of course and slap the side of the bow quite loudly in passing, but they never broke. The other thing is that these arrows were not damaged or split in any way because I always checked them before shooting and still do.

Having said that, I am sure that there would be a draw weight where I could expect wood arrows to break, but my guess is that it would need to be more than 15lbs underspine. I cannot speak about carbon arrows, and I have certainly heard a few horror stories of them shattering, but I do not know the cause of this. I have never seen an aluminium arrow shatter either, but I would have thought that modern syntharrows would be able to withstand far greater columnar forces than any wood arrow however.

Something to ponder anyway.
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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