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Info to include when you want help / glossary

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61K views 39 replies 16 participants last post by  Kmart2023  
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#1 ·
In Light of so many requests for "recommendations" I thought this thread might help.

First of all AMO or Archery Manufacturers and Merchants Organization put out a document that has all the "Standards" that we as archers use. They used to be at www.amo-archery.org but that website seems to now be a search portal.

You can find the document if you search a bit. I found a copy here. http://www.thearcher.com/depot/resourceCentre/AMOStandards.pdf

Since the internet can be such a poor communication medium, Let's see if we can help guide you in advance.

Things that help us as instructors/coaches with guiding you. (if you have this info in your signature that works too)

If you don't know, that's OK we can ask questions to guide you but this may eliminate some of the "I need help with " followed by several responses asking all the questions over and over.

Obviously not all the information may be necessary but the more information you give the community, the better we can help you.

Subject
What does your request involve? Tuning, form, basic instruction, arrow selection, equipment recommendations, etc


In the Skills/demographics category

Level of archer, beginner, Intermediate, advanced, competing.
If you want to be more objective maybe distance and scores. ie 18M 40cm Fita target 275/300
Style of archery. (barebow/traditional, Recurve, Compound) and class/age/gender (youth, young adult, adult if you don't want to give your age)
How long have you been shooting? Have a coach or self taught
Left or Right handed. (eye dominance if you know)

In the Equipment category

Left or right handed.
Exact equipment using.

For example a basic request might include.
RH, Hoyt GM, 25" td4 series. 36" medium limbs. 8125 string. Single rod Stabilizer. no vbars, Plunger, basic sight, etc..

Shooting equipment,

Tab, Glove, release (if compound)

Arrows if known, length of arrow spine/series, vanes, feathers, type and size, Point weight, nock type, etc.. The more information the better.

Symptoms
Arrow flight. (fish tailing, Porpoising, spiraling)
Bare shaft lands where at what distance?
nock position (high right compared to fletched arrow
Group size at what distance?

if a form question, "arrows group low left as I tire", or "can't keep pin on target as I get to 70M"

Setup and measurements

Draw weight at what draw length. Calculated or measured..

NOTE: Draw length is measured from bottom of nock grove to the pivot point (where the web of your palm presses into the grip) +1.75"
NOTE: For best results draw weight should be measured with a scale but calculations are better than nothing.

String info should include type, strands, serving type, nock type.

Other setup info that is helpful, Brace height, tiller, nock height, exact brands if possible.

Arrow info for more technical questions should include make/model/spine. Length of arrow, Point type/weight. Nock type.

Goals or outcome desired

What are you trying to accomplish with this inquiry?

Be realistic and Honest.
 
#2 ·
Really great info, and thank you and others who are so willing to offer help and share your knowledge.
 
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#5 ·
Arrow spine defined..

AMO (see above) in the effort to standardize manufacturing and marketing put forth some guidelines that all MFG's now follow for rating their arrows.
In simple terms, the larger the spine number, the weaker the arrow's spine is.

The way it is measured.. An arrow is supported near both ends at 26" then a 2 lb weight is hung from the center. The distance the arrow deflects under that weight is the spine measurement (in thousandths of inches) so 2000 spine would be 2" deflection.

The above is "static" spine or the spine rating a MFG puts on the arrow. In theory static spine should be exactly the same from mfg to mfg..

Dynamic spine is a little harder to explain.

In simple terms, Dynamic spine is the "affected" bend put on an arrow when we let go of the string. This is affected by a huge number of factors which I (or someone else) will try to explain in another reply.

Archers Paradox
Archers paradox is related to spine so I will put it in here..
Technically "archers paradox" or "The Archers Paradox" is the term "Straight as an Arrow". The paradox is, When we release an arrow, it is NOT straight.
What causes it to be bent? and how does that affect us. That will also be explained with the "dynamic spine" post.
 
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#14 ·
dchan said:
Archers Paradox
Archers paradox is related to spine so I will put it in here..
Technically "archers paradox" or "The Archers Paradox" is the term "Straight as an Arrow". The paradox is, When we release an arrow, it is NOT straight.
What causes it to be bent? and how does that affect us. That will also be explained with the "dynamic spine" post.
Click to expand...
Almost forgot this..
What causes it to be bent?
When we draw the bow back, we store a great deal of energy in the limbs.
Regardless of tune and everything else, when we let go, (or release the string) all that energy has to go somewhere.

In a perfect world, the bow would be perfectly tuned. the string would begin it's travel forward in a perfect straight line (is your "bow in plane") and the arrow would be sitting perfectly center shot.
Your release would be perfect and all of the energy would be directed straight towards the target, STRAIGHT through the arrow and to the arrow point.
With all this energy being perfectly focused through the walls of the arrow towards the target there would be even pressure on both walls of the arrow and it would not collapse in any way and the arrow would stay perfectly straight. In this perfect world, the arrow walls would not compress at all and 100% of the energy would get transferred to the propulsion of the arrow and it would go exactly where it was aimed.

In the real world, our tune is never "perfect" and our release is never perfect. So lets presume you got a pretty good "eyeball setup" with your bow. (won't go into that here)
For a right handed archer, As you release the string you WILL push the back of the arrow towards the left. Because we are trying to put the energy somewhere, Arrow wall material can be compressed (to a degree) and we have to overcome inertia, (point of the arrow is heavy and doesn't want to move) the energy will cause the rear of the arrow to move before the front of the arrow. Because we "pushed" the nock end of the arrow to the left, it will start to move to the left. This will cause the arrow to "buckle" a little and bend with the middle of the arrow moving to the right.

Once we overcome the static inertia of the point of the arrow and now the whole arrow is moving forward, there is no longer enough force or energy to keep the arrow bent, The arrow will try to straighten out or recover from the bend we just put in it. With nothing to keep the recovery from stopping once it is straight it will flex and bend the other way, back and forth until all that energy is expended. Usually most of the way to the target..
 
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#6 ·
Arrow numbers defined
If you were wondering what that four digit number is that you see on most aluminum alloy arrows (x7, xx75, Platinum plus, jazz, etc)
The first 2 digits are the outer diameter of the arrow in 64ths of an inch.. IE: 17xx would be 17/64"
The second 2 digits are the wall thickness of the arrow in thousandths of an inch.

For example. 1916 arrow would have an outside diameter of 19/64" and a wall thickness of 16 thousandths of an inch.

The type of alloy will also determine some of the spine. The harder alloy like what is used to make an x7 will bend less but be more brittle. The xx75 or xx78 alloy will a softer alloy and will bend easier and take a bend easier but less prone to shattering. They generally will bend when they hit something hard where x7's tend to fracture or shatter.
 
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#9 ·
What affects Dynamic Spine?

So what affects dynamic spine? Just about everything.

As mentioned so many times FORM trumps a great deal of other things. Bad release, slow release, dropping the bow arm early, creeping, overdrawing, plucking the sting, peeking as you release, etc... All these will affect any tuning attempts you make.
This is why above I mentioned that part of the equation for help should include your "level of shooting/experience" as well as a score (which would be an objective indicator)

On the setup side, Centershot, tiller, brace height, actual draw weight (weight on the fingers). nock height, string material, string construction, strand count, serving type, length, things attached to the string, nock locator type, arrow static spine, stabilizer type and weights, etc etc etc.. You get the picture?

So what helps when we start trying to give advice?

As much objective information you can supply. Again be honest. false data given produces false recommendations and much frustration. (garbage in garbage out)

Things we as archers can change as far as arrows and bows that drastically change arrow spine(discounting form here)
spine larger number = weaker dynamic spine
arrow length Longer arrow = weaker dynamic spine
Point weight heavier point = weaker dynamic spine
nock weight Heavier nock = stiffer dynamic spine
FletchingHeavier fletches = stiffer dynamic spine
arrow wrapsaddition of arrow wraps = stiffer dynamic spine.

Things on the bow we can easily change
Draw weightmore weight = weaker dynamic spine
String
slower strings (more strands or material change) = stiffer dynamic spine
thicker or more center serving (makes the string heavier/slower = stiffer dynamic spine
Nock locator, lighter (such as tie on locators) = weaker dynamic spine
setup Center shot, plunger etc.. Use tuning manuals to assist with this and bare shaft tuning.

Brace heightwhile this does affect dynamic spine I try not to use this adjustment for this as it also affects a lot of other parts of the tune. Primarily how the arrow releases from the string.

There are many more things that will affect dynamic spine that I decided not to include (especially about form). The idea here was to help people give more useful information for when we try to respond to questions.
 
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#10 ·
Time to add here.

Form questions

Instruction: Self taught - simple instruction - internet searches - Actively working with an instructor or coach.
Form type: Basic, NTS/BEST, Traditional, Compound converting to recurve, etc..
String hook: Fingers on string split finger, (one over, two under) 3 under, string walking. Here would also be a good place to tell us glove/tab/type if you know.
Anchor: side of face, under the chin, under the chin with string touching the nose, "WHAT's an Anchor?":mg:
Stance: Open, closed, square.. What else are you thinking about for stance.
Practice sessions: How often, how many arrows, how long?
Gear: should have been covered but just in case, equipment

And Video/pictures..

The more the better for form questions but some suggestions.

Overall view/Front view (from the shooting line) capture the whole body. not just the torso.
Front view (from the shooting line) Get a closer up view of the face and chest area.
Back View (from behind the shooting line) straight back so we can see the alignment of your elbow arm, etc.. About elbow height.
Overhead view (from behind the shooting line) looking down at the archer, facing forward. Try to capture from the drawing elbow to the stabilizer
Rear view (from the shooting line in back) 3 things here. overall view including stance. Closer up view of the upper torso and head, and close up view of the clicker (helps seeing video of clicker control)
and if possible, (have a tripod and are comfortable leaving your camera in front of a shooter) front view. Torso and up, as well as a good shot of the bow hand..

Of course your mileage may vary and not all the views are always important, especially if you are asking something as specific as "how's my clicker control?" however..

If you can only get one or 2 shots, overall view from in front, along the shooting line, and behind the shooting line straight back maybe just over the head level looking towards the target would be best.
 
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#12 ·
Tests to include if you have done them.

Bare shaft tuning? what were the results. See "tuning for tens"
http://www.texasarchery.org/BoardMembers/RickStonebrakerPages/TuningForTens/TuningForTens.pdf

Clearance tests.
If you don't know what we are talking about,
The idea here is to check if your arrows and vanes are clearing the rest/plunger/riser properly. (see the archers paradox video above)
To do this, using some sort of powder or marking material (lipstick, foot powder, talcum powder) you can either coat the riser plunger area with powder or put some lipstick on the edges of your vanes.
Shoot a few arrows and look for marks or impressions left on the riser. If you used the lipstick method and you have contact, there will be lines of lipstick left on your riser. If you used the powder methods, you will see voids where the feather or vanes swept through the powder.
Also if you used the lipstick method, you can look at your arrow vanes and see where it was rubbed off.

If you have access to a high speed camera (like the casio exlim) or if you are real lucky a commercial HS camera, high speed video will often capture impacts as well.

Walk back:
Here's something that may help with arrow flight questions besides bare shaft shots.. Just doing a walk back shooting at different distances can sometimes tell a lot.

Couple of ways to do walk backs for different outcomes.

Set up a target point, high on the bale and use a 18M sight mark to verify.
Walk back to 25M. and shoot several shots (using the same sight mark and spot to aim at.. DON'T change anything on your sight)
Then back to 30M and repeat, etc until you run out of space on the target.
The results should be wider and wider patterns further and further down the bale. Drift left/right tells us setup or tune.. Believe it or not it's possible to have drift both directions at different distances.

Another walk back, similar activity has you changing elevation on your sight but not windage. The results can tell us several things as well.

In both of these tests we are looking for the group's position, no so much size of the group. The better your form is the tighter the groups will be but don't try to adjust for the drift left right at this point.
 
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#15 ·
and bouncing around a little..

How to give us weights and measurements
Since every one is built different and so many things depend on this to help with arrow selection.

Give us the specs of your equipment. ie:rated draw weight, length of limbs, etc.. (see the equipment section)

The measured weight on your fingers (OTF is what we usually see for abbreviation) and if it was measured or calculated. Measured is better but calculated is better than nothing
Your draw length (See AMO specification). Again measured is best. Calculated is ok but let us know if that was the case. The best way to measure is to draw a bow back with a long arrow and have someone mark the length. Then measure the arrow using the AMO specification to calculate from where the arrow was marked. I usually mark where the plunger/hole that is just above the grip is, since that is almost always in line with the pivot point of your grip.
AMO draw length are what all the bow(and arrow) charts are calculated from.
 
#19 ·
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#21 ·
Reading the Easton arrow chart and how to get the best result from it.

It has come up several times that the Easton chart is "way off"
While I agree it's not perfect I have found it to be fairly accurate if you make all the adjustments and measurements that are outlined..

Don't use the web based software until you go through all the measurements to get the right information to plug into the selector.

Be aware that the Easton chart has several "conditions" and "measurements" that don't necessarily match the AMO standards we all use. You need to correct for all these differences including how they measure "correct arrow length" as compared to AMO draw length.

They list "correct arrow length" as 1" past the last contact of the arrow rest. For many bows, this can be 1" past the back of the riser (in the case of a longbow shooting off the shelf) to 1/2" or more short of the back of the riser. Since AMO (and draw weight is measured by AMO draw length of 28") and they use a different reference point to measure from (AMO uses the pivot point of the grip) you can see there are a problems here.

According to the chart instructions, to determine peak draw weight (a compound term by the way since recurves don't have "let off"), Peak weight must be measured at your full draw for recurves. Using the rated weight at 28" will put you way off. Poundage on the fingers is what needs to be entered on in the charts and selector. Since several ILF's have a range + and - depending on if the bolts are cranked in or out, and limbs don't all gain or lose weight at exactly 2# per inch, Calculating this based on the "rating" on the limbs along with adding or subtracting for draw length will never be quite right. MEASURE instead of Calculate if you want to be more accurate.

Then look at the chart group.. Easton uses group 00-03, then T1-T14 for groups. Keep in mind that the chart almost always covers many different arrow types and many arrows will fall into a "group" T2 for instance goes from 750 to 910 depending on which arrow you select. So just because a specific Carbon 0ne falls into this range, (810) if your calculations and arrow info put you barely in the T2 group, 910 might have been a better spine. It's just that Easton does not make a 910 spine Carbon One. So we have to make adjustments by changing point weight or leaving arrows longer, or some other adjustment.

For the record, the chart "presumes" a point weight of 100grn. and specifically mentions that if you go up or down from that 100 grn, you need to adjust the spine some.

AGAIN: The charts are designed to "get you in the ball park" and will not be perfect. From my experience using the charts for several decades now, they will almost always get you within 1 spine when read with all this extra info.

Another note about Easton's spine charts.

The formula that Easton uses for spine is
arrow supported at 29" and a weight of 880 grams (1.94lbs) suspended in the center. Deflection is in thousandths of inches
AMO uses arrow supported at 26" with a weight of 2 lbs suspended in the center. Deflection is in thousandths of inches

With out actually doing the testing using both methods I can't say if they are the same but I suspect that since more mfgs are now making arrows longer than 28" they had to make an adjustment to allow for the longer arrows.
 
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#23 ·
Acronyms we often use. in no particular order. Feel free to add on.

BH = Brace Height or string height
OTF = On The Fingers
TP = Target Panic
AMO = Archery Manufacturers Organization
ATA = Archery Trade Association
IBO = International Bowhunters Organization
ILF = International Limb Fit Also known as the HDS
HDS = Hoyt Dovetail System. The patented name for the ILF system we use.
TD = Take Down
GPI = Grains Per Inch
 
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#25 ·
Hmm thought arrow measurement was in here but was wrong.

The standard way to measure arrow length is measure from the bottom of the nock grove to the end of the arrow shaft. We don't include the point or insert in this measurement.

Most MFG have the specification on their pages that will tell you what the uncut or "stock" arrow length is.
Also most have the diameter and weight of the arrow shaft in Grains per Inch or GPI

DC
 
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#27 ·
Riser, limb and total bow length.

Some how missed this.

When looking to purchase gear.

For MOST ILF Olympic gear, risers come in 21" 23" 25" and 27"
There are a few risers out there that are 24"

ILF limbs come as Long, medium, short and extra short.

Very often the limbs have noted on the dovetail section what length bow would result as well as poundage on a given length riser or (H)andle
25" riser + long limbs = 70" overall length.
Medium limbs = 68"
Short limbs = 66"
Xshort = 64"

23" riser + long limbs = 68" overall length.
Medium 66"
Short 64"
Xshort 62"

And of course going to 27" riser add 2" to the 25" numbers.
 
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#28 ·
Carbon Express arrow spine chart ala Limbwalker.

Attached is Limbwalker's spine chart for Carbon Express including Medallion XR's

You may have to download it to read it..

I'll work on cleaning up the image some.

View attachment CX spine selection chart (Magera).pdf
 
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#29 ·
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