Spine /Center shot
 

Another question in my obsession for perfection. Does spine effect center shot? If I shoot two different spined arrows from the same bow will I need to adjust my center shot for both arrows. #2) What is the tolerence of center shot? Is it an exact postion or can it be as much as an 1/8 inch right or left? Once a bow is set for a shooter does center shot ever change? JERRY

RE: Spine /Center shot
 

Jerry:

Looks like you' re not getting too many takers on your questions.

Let me just tell you this. Centershot is as about as misunderstood as many of the other ' tuning' concepts derived by those trying to achieve a basic description. Many will get frustrated by not having ' absolute' answers and seek other means of archery which is not so demanding.

Even if you use the most sophisticated center shot tools, you still have other variables with which to contend and which will alter that setting. Given that centershot tools work on a static bow situation, it many times will give you a wrong setting for dynamic (bow at full draw) situations. The centershot tool also demands that the surface where it' s being mounted is absolute with it' s relativity to the other components and surfaces of the bow.

Some of the things that will negate ' factory type' suggestions, centershot tool suggestions, or ' internet forum' suggestions for centershot are; the amount of tolerancing you have in YOUR bow, the type of rest that you have on YOUR bow, and how much YOU torque YOUR bow with either YOUR bow hand or YOUR release hand.

One other thing that we have found that will affect centershot quite a bit on certain types of rests is how much the cable guard flexes at full draw. This will become, of course, more prevalent with higher brace height bows where longer cable guards are required. In effect, this is one more advantage of the Hoyt ' Tec' riser designs.

Now, I' ve probably opened up a ton of questions. Hope this at least sheds some light on the subject; but, please don' t expect me to expound on these tidbits of information. It would take a small novel.:D

RE: Spine /Center shot
 

It' s the weekend Len. I firgured I' d see more when all the techues get back to there shop or computers. Thanks for taking the time. You bet I got questions.lol I wish there was a book or video that had all the info about bows set-ups and tuning. I have some but I' m looking for the advanced advanced course. I think I know most of the answers to this post. I just wanted to confirm them or ajust my thinking if I' m wrong. I know torque is a big factor but I' m not too sure about spine. I usually eye ball center shot initially then shoot it in at the range. Mechanically it works for me I just want to understand the theory. JERRY

RE: Spine /Center shot
 

Yes spine affects center shot. Len are you talking about the rod flexing at draw, or being under to much stress to begin with.Ive seen problems when people set them up for to much arrow pass,and have side stress, but never even really thought about the flex difference at draw.Len your cable guard answer brings up another question from me. Are there certain brands of bows that are more likely to have this problem, and what has the least amount of twist. Offset, or straight, and Carbon rods or steel.

RE: Spine /Center shot
 

Fletchead:

It varies with riser design and the type of material that is used. You saw me mention the ' Tec' riser being better at controlling this problem. The reason is quite obvious in that the rod length is supported in two places and the distance from the ' Tec' end to the end of the cable guard is subsequently much shorter.

The material composition is a key factor. For instance, if an aluminum rod is used, what grade of aluminum did the manufacturer select? I did have a major problem with a customers bow and proceeded to remove the carbon rod and replace it with a steel rod. The problem was eliminated.

RE: Spine /Center shot
 

Len,was that a major problem on the old Hoyt Raptors.I had someone bring one to me to tune and this thing just wouldn' t act right.It acted like the cable guard was loose.It was loose but I fixed it and it got better but was still doing the same thing.Couldn' t get the thing to paper at all.It kept showing a stiff arrow,regardless of the adjustments I made.I also suspected bent limb pockets but had no way to check.


I did a lot of twisting and turning on this bow and got it shootable but I never was satisfied.

RE: Spine /Center shot
 

This is great , good info to apply to our never ending quest for " perfect arrow flight " . I' d like to add some questions here . If you keep the center shot the same and use a stiffer spine will the arrows walk to the left with a right hand , compound , release shooter . With the resent threads on broadhead tuneing in my mind arrow spine seems to be about the most critical aspect that is easyly changed to correct poor flight " with broadheads " . Since easton says bare shaft tuneing is for finger shooters does that mean it does not aply to release shooters ? I' ve heard others say they use it with releases . And lastly [ not to open up anoter can of worms ] but if trying to get broadheads and field points to hit the same is' nt viable , why does easton list it as a tuneing method ?

RE: Spine /Center shot
 

TFOX:

Yes, the Raptor (among some of the others) could be a ' bear' to tune. It had a steel rod and could shift if the guard was not locked down tightly with all the set screws provided. The design of how the rod was mounted was so good that they kept it for a while, didn' t they? :D

Back then we pay too much attention to the cable guards. Now we do! Like you, we just tried like heck to tune around it.

ijimmy:

You' ve got too many questions. I think you' ll have to take my course. ;)

RE: Spine /Center shot
 

Len if you were' nt have way across the country I' d probably be pounding on your door :D . By the way I' ve got my mavric recurve shoot' n good useing a trophy taker , it likes that rest and is alittle quieter with it than the zerro effect I had on it . I' ve got to get it shoot' n dead nut' s before season as the guy' s in Pa where I hunt say its the only bow I can kill a deer with up there , they love their darton' s .

RE: Spine /Center shot
 

Hey Len,the best way I found to tune this thing was to just grab the grip.It seemed the induced torque was what this bow wanted.I didn' t even try to teach this person how to properly hold a bow because his bow reacted horribly to a loose grip.Didn' t like it but it worked.

RE: Spine /Center shot
 

Fletchhead spine has absolutley nothing to do with the center shot of the bow
center shot is the relationship of the center of the string to the center of the arrow from nock to tip.
when the string is released the string will push the arrow off of the rest strait if everything is properley aligned
the strength of the arrow has nothing to do with whether or not it is coming off of the string strait.

RE: Spine /Center shot
 

Yes I understand that. There is a true center shot for every bow.The point I was making was in answer to the question, does spine effect center shot. Yes it does, along with many other factors. Shoot an under or overspined arrow and see if rest position changes in order to get an " Acceptable rip. Maybe Len will jump in here again and word it better, but the way Ive always seen it, there are two center shots. " True center" , and " Induced center."

RE: Spine /Center shot
 

Fletchhead,

I am in agreemant that true center doesn' t change and that induced center will.I however believe that if you try to get good tears out of poorly spined shafts that it will be hard to group.You would be better off just group tuning and live with the tear in paper.


This is why a lot of tournament shooter say to forget the paper.I don' t agree because the paper can tell you a lot but isn' t the gospel.If your spine is perfect or near perfect you will see almost perfect holes after group tuning.After group tuning a setup with arrows that the spine is off,you will have a tear in paper.

The funny thing is that all the ones that say to forget the paper seem to have a paper tuner setup somewhere.[&:]


So much easier and I have found it to be much more forgiving to just have the right spine and all the headaches are gone.Well most of the headaches.;)

The person behind the machine has to do his part.:eek:

RE: Spine /Center shot
 

I thought I' d get more of the heavys out on this but since they' re not biting I' ll throw out this out for debate. NO. Spine dosen' t effect center shot to my knowledge. Once I set up my bow to an arrow with proper spine and shoot in center shot at longer distances it should never change. Thats the sweet spot of the bow. I have never changed spine by adjusting center shot or visa versa. I achive proper spine by poundage or point wt. I have effected spine or got some forgivness from spring tension but the two don' t have any correlation. In my quest for the perfect tune I have read moving your rest to bring the field points and B/H' s together is incorrect for the best tune. Unless there is some sort of engineering myth or math theroy I' m missing moving your rest and center shot once it' s establish is tabu. IF what I have said is true then what is the best indicator for spine. Bare shaft or paper. Or something else. JERRY

RE: Spine /Center shot
 

Fletchhead
I understand what you are saying but center is center yes an underspined arrow normally will go low and left. you would be better off leaving your center shot alone and back off of the poundage to achieve the results you are looking for.

I agree that paper tuning is a good way to assist in tuning a bow in relation to the flight of the arrow.
but If you cant get good groups or hit where you are aimingat 20 yards away from a bow that will shoot bullet holes through paper 6 feet away paper tuning is useless. JMO

RE: Spine /Center shot
 

Jerry I have found the best indicator of spine is ARCHERS ADVANTAGE:DNo seriosly.I think 2 of the best ways is to paper a bare shaft and a fletched shaft at about 4 ft with the center shot set.This will tell you right away if the arrow is kicking.Then back up and it remains good through the paper.Now it is time to fletch and go out and group tune.I will add this though.Since using Archers Advantage ,I havn' t had to change anything to achieve that perfectly spined arrow.It has always been right.



In my way of looking at it is if you have to move the rest to get bullet hole because of spine.The induced center shot is changed but the true center has not.Center is center.

RE: Spine /Center shot
 

In my way of looking at it is if you have to move the rest to get bullet hole because of spine.The induced center shot is changed but the true center has not.Center is center.


T fox HELLO my thoughts exactley
and yes that is the best program That is what I use also.

RE: Spine /Center shot
 

TFOX what effect does fletching have in the first 4 feet of flight ?

Bigpapascot I thought weak arrows went to the left when bareshaft tuneing or broadhead tuneing . Low and left according to what , I dont get what you are trying to say here .

RE: Spine /Center shot
 

Jimmy
I only paper tune with fletch on from 6 feet and I dont shoot broadheads thru paper either really no sence in it if you can get bulletholes from an arrow with the same weight field point as the broadhead the results will be the same
group tuning is the best way to work with broadheads, bare shaft tuning is a wayste of time JMO
a weak arrow will shoot offset and low depending on which hand the arrow is shot from, the weaker the spine the farther offset and the lower the shot will be at least that is my experiences with weak spined arrows.

RE: Spine /Center shot
 

The position of the arrow on the bow (centershot, or the amount of deviation from center) among other factors, will dictate which arrow spine flies best from the bow. Centershot bows, for example, require a fairly stiff arrow. Bows that are not centershot require progressively weaker spined arrows the more the bow deviates from being centershot. This is due to arrow paradox, the flexing pattern the arrow takes as it leaves a bow. An arrow must go through greater paradox to pass around the risers of bows with less centershot than bows that are more centershot. Hence, the arrow must be of a weaker spine to be able to flex properly.

The risers of most modern compounds are cut so the rest can be positioned in the center of the bow...which makes tuning and shooting less critical than older style non-centershot compounds and very-far-from-centershot traditional bows. If the proper arrow spine is selected, however, good arrow flight can be achieved with both centershot bows and non-centershot bows...even on 1.5" wide English longbows where the center of the arrow lies over 3/4" from center.

Back to your original question...Assuming both your arrow spines fall in the " tuneable" realm of your bow (and aren' t so close in spine that the difference is not noticeable), you may find that the weaker spined arrows will perform best when the arrow rest is moved slightly away from center. :eek:

RE: Spine /Center shot
 

ijimmy

It really doesn' t make a difference but fletching can be used to play with spine.You can move the fletching forward and shoot a slightly weaker spine.I don' t do this but have been told by some pros that they have done this to get a shaft to react stiffer.The main reason I said to shoot a fletched arrow was to make double sure there was no contact but you can do that from further back,doesn' t really matter.


Just something I like to do to see what is going on at several distances.

RE: Spine /Center shot
 

AK,I agree that a weaker spined ARROW will perform best when moved slightly away from center but for me,I don' t perform better when the arrow isn' t being shot at or close to center shot.The arrow comes off straighter but the shooter has to be able to hold the bow on the spot.When the arrow is at an angle coming off the bow you must compensate as the shooter.I feel like I am shooting across my body and can' t get good groups.The results are a lot of lefts and rights.I don' t know if this makes since or not

One of the main reason that we need to group tune is to find out where we like to shoot.