Arrow Tech

Some of the stuff below you may know, some of it you may not.
The last thing I ever want to do in the archery community is to “teach my grandmother how to suck eggs”, so please feel free to cherry pick the info that you need…

Arrow techTerminology…

Arrow Length

This is one that often trips people up and one that I always have to double check when customer give me details.
In actual fact measuring “official” arrow length could not be more straightforward (see pic)

Measurement is taken from the “throat” of the nock (where the string sits) and up to the end of the shaft where it goes into the back of the pile or where the rear of the screw-in point starts

If you need to quote your arrow length at any time it is this “industry standard” that should be used.

arrow length.

Spine (static)

This is the amount of flex, or bend, an arrow shaft has.
A powerful bow requires a stiffer spine than a weaker bow and vice versa.
Shooting a bow with a spine that is far too weak can result in the shaft breaking and causing severe injury to the archer!

Carbon fibre arrows will be marked from weak (1600 spine for example) to a very stiff shaft (300 spine for example) but the most commonly used “spine values” will lie somewhere in the middle of those figures (see chart below)…
The correct spine value for you will be determined by the poundage of the bow and the required length of arrow for your draw length

RHA Carbon Spine Chart

Wooden arrows are not usually marked with their spine value but will be sold from weak (30-35 spine for example) to a very stiff shaft (85-90 spine for example) but the most commonly used “spine values” will lie somewhere in the middle of those figures (see chart below)…RHA Wood Spine Chart

Spine (Dynamic)

Dynamic spine refers to the actual level of arrow tuning when in use, rather than just a static shaft as shown in the charts above.
When you release an arrow from your bow it will require the correct amount of “paradox” (how much deformation/bending is induced into the arrow shaft by the power of the bow) to suit the bow you are using.
For example, a bow with a cut-out for an arrow shelf will need an arrow that bends less than a bow without a cut-out (ie. any bow that you shoot “off the hand”, like an English Longbow or most Asiatic bows)
Dynamic spine can be “tuned” via length of the shaft, the weight of the point (or point and insert combination) and the chosen static spined shaft itself.
Getting the right dynamic spine can be done by experimentation, experience via previous arrow builds, or contracting an arrow tuning specialist and giving them the relevant details.

At the time of ordering with Robin Hood Archery I ask for:

  1. Make & Model of bow
  2. Bow poundage (either on your fingers or the standard “at 28”)
  3. Your draw length
  4. Whether your bow is fitted with a performance string
  5. Intended category of use for the arrows
  6. Whether you shoot left or right handed (for wooden arrows only)
Straightness Rating

Used solely for carbon arrows. On carbon shafts you will see markings such as “Straightness: +/- 0,006″ or something similar (see pic in the GPI section)
This refers to the amount of deviation from absolute straight, in fractions of an inch, over the course of its length.
Although 0,006″ is in the lower category of tolerance it is perfectly acceptable for the majority of traditional archers.

The next levels up would be 0,003″ or 0,001”. Personally I am more than happy to shoot 0,006″ or 0,003″ as, at those levels of tolerance, the arrow is going to perform better than I ever could anyway. Ive never used 0,001″ and, as nice as they undoubtedly are, I wouldnt be willing to pay the extra premium for them. Thats not to say that they havent got their place in the right circumstance 🙂

Ive heard people say “straightness doesnt matter. My bamboo arrows have bends in them and I still hit what I aim at”.
So is straightness in an arrow important? Of course it is! Anybody who says otherwise is kidding themselves.
Straightness (and Im even talking about 0,006 here) means consistency and consistency should be the goal of ANY archer. This leads us neatly on to wooden arrows…

A word about straightness in wooden arrows:
A reputable supplier will not send out arrows unless they have been straightened. Sadly, that doesnt happen all the time and is probably neglected far more often than it should.
So, do you know how to check your wooden arrows yourself? (more on this shortly)

If you shoot wooden arrows they WILL get bent as you use them. A fact of woodie ownership is that they require more care and maintenance than carbon or aluminium arrows.
It is essential that you check them periodically AND have the means to correct any deviations in their straightness.
In the following link you can see my method for straightening wooden shafts and see the equipment I use…
https://youtu.be/fsrg3_XH5_4

FOC (Front of Center)

FOC refers to the “balance” of the arrow and how much of the total percentage weight is in front of the absolute center of the arrow

FOC diagram

I use an online FOC calculator to save my brain hurting…
https://archerycalculator.com/arrow-front-of-center-foc-calculator/
If you can tune and arrow and also tune the FOC of an arrow then you are well and truly into the dark arts!
In short, a small % FOC will be great for target shooting etc and a larger % FOC could be great for short distance shooting and/or hunting.
Reckon on aiming for a tune of between 8% and 18%. For field and 3D shooting I tend to steer towards between 14% to 17%
*Higher and lower % are of course possible and a large part of this aspect of tuning will come down to personal preference

GPI – Grains Per Inch

Grains per inch

When dealing with arrows and arrow components we always use grains as the unit of measure.
GPI (grains per inch) usually refers to how heavy a shaft is, especially on carbon fibre arrows.
Example:
If a shaft is marked as being 7gpi and you know that your finished shaft length is going to be 28″ then we can multiply 7 by 28 to give the total weight.
In this case 196gn.
The finished arrow weight will be this figure plus any other components added such as insert, point, nock, fletching.
In practice the gpi marked on the shaft is more of a method of comparing different shaft models of the same “spine value” with each other.
Something with a very light gpi may not be suitable for the rigours of the 3D course for eaxmple. Conversely why would you use a heavy gpi for target shooting?

GPP – Grains Per Pound

GPP, or grains per pound, is used in reference to a particular bow being used. Let me explain…
Some bowyers/manufacturers will stipulate that a minimum GPP of arrow should be used by their bow. This is to stop over-light arrows shaking a bow to pieces!
It is an easy calculation:
If a bowyer states that your bow should not go below a minimum 9GPP and the bow is 40# the the calculation is…
9 x 40 = 360gn (this being the minimum total arrow weight that you should shoot with that particular bow)

Arrow styling – overview

When it comes to arrows I pride myself first and foremost on RHA’s arrow tuning and matching the correct arrow setup to the archer and their equipment.
As well as RHA tuning services I also offer a vast range of styling options.
To clarify some of the base options open to you I will attempt to define them for you 🙂

Crowning (any arrow type): a base colour to the “crown” (nock end) of the arrow. This can be solid paint or an opaque stain (stain on wooden arrows only). Crowning can be ANY colour but bright options are favoured to help in locating wayward arrows. Can be applied with or without cresting.

Cresting (any arrow type): Blocks and rings of colour used to personalize an arrow set. Design possibilities and colour combinations are endless.
Designs can even incorporate numbering rings for competition use. Can be applied with or without crowning.

Stain (wood arrows): Wood stain applied to all or part of the shaft. As well as traditional wood tones I can also use paint colours to stain shafts (see photo “Stained Crown with Cresting”) Staining can be applied on its own or in conjunction with crowning and/or cresting in any combination.RHA Design services are free of charge and I work closely with customers to develop designs to fulfill their needs.

Crowning
Crowning

Crowning (any arrow type): a base colour to the “crown” (nock end) of the arrow.
This can be solid paint or an opaque stain (stain on wooden arrows only). Crowning can be ANY colour but bright options are favoured to help in locating wayward arrows.
Can be applied with or without cresting.

Cresting

Cresting (any arrow type): Blocks and rings of colour used to personalize an arrow set.
Design possibilities and colour combinations are endless. Designs can even incorporate numbering rings for competition use.
Can be applied with or without crowning.

Staining

Stain (wood arrows): Wood stain applied to all or part of the shaft.
As well as traditional wood tones I can also use paint colours to stain shafts (see photo “Stained Crown with Cresting”)
Staining can be applied on its own or in conjunction with crowning and/or cresting in any combination

A word from Kev Arrow Smith

I have been making and tuning arrows professionally since 2013. In that time I have been fortunate enough to acrue a huge amount of experience in the field.
That said, there is always something new to learn and with each new set there is for ever the possibility of stumbling across new or improved ways of going about things.
I like to keep an open mind and a particular mantra always in my head…
“There are always a thousand roads to reach the same point”.
That sums up arrow making and tuning in particular 🙂

I will add to this page as and when extra “tech” to add springs to mind. In the meantime, if Ive left any glaring holes, please let me know so that I may fill them.