How and why do we tune our bows
This question comes up in several forms from time to time,
so I thought it would be a good idea to give an overview about tuning a stickbow. Why, when and
how.
First thing we have to understand that a bow, ANY bow, be it a longbow,
recurve, compound or crossbow, regardless of how well or poorly tuned when
strapped to a shooting machine will stack 12 IDENTICAL arrows all day long.
(That’s providing the physical properties of the bow or environmental conditions
don’t change during the session.)
Notice I didn’t say that the arrows will necessarily come out flying straight, nor
will they necessarily hit where you want, only that they will behave exactly the
same way. That’s kind of a basic law of Physics.
First question:
So why are we tuning our “stuff”?
Well, most of us would like our arrows to come out of the bow straight, and it’s
not unreasonable to want them to hit what we’re aiming at – at least most of the
time.
A clean (or straight) arrow flight means that the least amount of energy is
wasted by the arrow trying to steer or correct itself. The less energy wasted, the
more is available downrange. That translates into extended effective range. If
you’re a target archer, that means greater accuracy at longer distances and if
you’re a bowhunter, not only can it give better accuracy, but better penetration
as well.
It also means that the bow/arrow combination will be more tolerant of minor
shooter error. Remember I said above that our hypothetical bow was strapped
to a shooting machine? Despite some reports to the contrary, we as archers ain’t
shooting machines. So a little tuning does help – more on that when we talk
about the “when” part.
Second question:
When should you worry about tuning?
Only answer is when you’re ready. Going back to our shooting machine
scenario, the bow is a constant and the arrows are theoretically identical so in
the real world, except for environmental changes (read: wind), WE are the only
variable. The best archers in the world can’t match the consistency of a
shooting machine. The greater the inconsistencies in a shooter’s form, the less
reliable his tuning data. Aiming aside, things like inconsistent anchor points,
unstable bow arms and even apparently minor things like string weight
distribution on each finger, pressure point of the bow hand on the bow, minor or
major shooter induced torque, etc. affect the arrow’s flight and point of impact.
That’s why we keep saying that you can only tune as well as you can shoot.
As an example, here’s how I tune an Olympic bow for a new shooter:
1. Set the brace height somewhere within the manufacturer’s specs (if you have
the right string, that’s usually a no-brainer)
2. Stiffen the plunger, so it is effectively a strike plate (removes a variable)
3. Set the plunger so that the arrow tip is to the left of the string, for a right handed
shooter (provides adequate paradox if the right arrows are chosen – and I’m
usually suggesting the arrows )
4. Set the ARROW NOCK approximately 1/8” above perpendicular to the string
and place the nocking point above the arrow nock.
5. Confirm that tiller is between 0/0 to 1/4” lower limb strong (again, that’s
usually the factory default)
6. Have the guy test the bow. If the arrows APPEAR to be coming out straight, THAT’S IT!
That set up will usually last for about 3 – 6 months, until the shooter’s form
solidifies. Oddly enough, more often than not, those standard parameters
usually prove to be either spot on or very close once formal tuning is performed.
Third Question:
OK, so how do we tune the thing?
Actually there are several methods and all have their place.
1. Visual inspection. Do the fletched arrows appear to be coming out and flying
straight? Yes, that’s what we did a while back and actually has merit. Gross
tuning corrections can be made on that basis for new shooters.
2. Paper tuning with the paper frame at 15’ can serve as a ballpark estimation
once form is fairly consistent. Note the term ballpark; I only use that method
when the shooter doesn’t have any bare shafts – hey it happens.
3. Bare shaft tuning, still the gold standard. I start at 10 yds for a sanity check
(just to make sure the un-fletched arrows aren’t going to go ballistic), then more
formal tuning at 20 yds. (That’s why I say that you really need some kind of a
recognizable group at 20 yds before you can tune successfully.) While the
planing method (relative impact points of bare shafts to fletched ones) is the
rule, I’ve found that nock kick-out (angle of the arrow in the target) corrects itself
as the bare shafts are brought to coincide with the fletched ones.
Basic rule of thumb for a right-handed shooter: a stiff bare shaft will impact left
of fletched ones with a right nock end kick-out, and a weak one to the right, with
a left nock kick-out. Bare shafts above the fletched ones means you have to
raise your nocking point and bare shafts below your fletched ones means lower
it.
4. Beyond that, we are really getting into things like walk-back tuning (for setting plunger position and
tension), bare shafting at extended distances and finally group tuning. These techniques
are more applicable to Olympic bows and / or more experienced shooters.
I hope that took some of the mystery out of what we mean by tuning a bow. It’s not hard to
do and the benefits can be significant once the shooter is capable of exploiting
them. Chapters 5, 6 and 7 in Shooting the Stickbow go into a fair amount of
detail covering both theory and practice.