Bare Shaft Tuning,

2478 Views 22 Replies 14 Participants Last post by GTOJoe, Apr 27, 2012

roy motley

Discussion Starter · Aug 3, 2006

How Do You Do This The Right Way, I Have Heard People Doing It, And Is It That Much Better Than Paper Tuning Or Is Uit A Waste Of Time When You Can Just Paper Tune And Be Done, Please Any Imfo Would Be Great....

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nuts&bolts

· #3 · Aug 3, 2006

AllenRead said:
Roy,

There was a good thread on this a short while back:

http://www.archerytalk.com/vb/showthread.php?t=315244&highlight=bare+shaft

George Dixon (Hunter54) had one of the better posts on bare shaft tuning.

Hope this helps,
Allen

Roy:

Bare shaft tuning requires a great deal of skill.
If your form is very solid,
and your bow is tuned well,
then bare shaft tuning will help you find the best combination
of draw weight, and arrow shaft length and arrow tip weight
to get the tightest groups.

Since a bare shaft also has zero steering correction,

then shooting a bareshaft will help you find the best position
for the nocking point/d-loop so you get level bareshaft flight.

You can even try creep tuning with a bareshaft
so you can really fine tune your cam timing.

Shooting a bareshaft for groups,
however, will also shine the spotlight
on form errors.

It's a powerful technique,
one of several tuning techniques.

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nuts&bolts

· #5 · Aug 3, 2006

This should be a sticky in the Tuning Section.

Excellent Post. Great stuff, Deezlin.

Deezlin said:
What so good about paper tuning?

The main reason, I prefer bare shaft tuning to paper tuning is you can't argue with results. If I can shoot an arrow straight into a wall at 20 yards and keep it on target. Then when it is fletched and shot, it is not losing speed trying to get straightened out. Paper only tells me what the arrow is doing at one point in its flight. It also help hunting arrow tune easier to field points because if the head is straight, the arrow already want to go there, the fletching can control the head better without having to control the shaft too.

Bare Shaft Tuning

This technique is used for release shooters. The primary requirements are a target butt that will hold an arrow the way it entered the target. I usually use a foam wall at my local club, but a block or some other such target will work too. The cable(s) and string need to be of the correct length and the bow should be within specifications. Dual cam bows should have the cables of equal length. This tuning process may not work for floating yoke cable bows.

The other requirement of this process is to using properly spine arrow shafts. A computer program should be used to determine the proper spine, arrow shaft length and point weight. These shafts can be float tuned prior to assembly to ease this process(see float tuning below). The arrow should be match for overall weight prior to fletching. The arrow should be properly aligned and squared on the bow. A Golden Key Futura, Tru-Center Gauge should be used to align the rest.

The purpose of bare shaft tuning is twofold. The first part is to adjust the bow for an ideal launch. This means trying to stick the arrow in the butt without the nock being kick up, down, left, right or some combination. All of this shooting HAS to be done with the target at shoulder height. The purpose of this is to reduce drag by relieving the correctional control of the fletching during the launch and flight. This also allows the use of smaller fletching to reduce flight drag and trajectory loss. The second part determines the high spots in the arrow spine and allows the grouping of the arrows to improve. Float tuning provides this same benefit, but is static. The type of tuning is dynamic and therefore is the final step. Basically, float tuning will get you close, but bare shafting is conclusive.

To start, shoot a couple of arrows at 10, 15 and 20 yards to get an approximate sighting adjustment. It is not necessary to pinwheel the target but to try to keep the arrows on the target. After you have sighted in at 20 yards, notice the way the arrows are hitting the target. If the nock is high-left we need to start making adjustments. Leave one arrow in the target as a reference.

Why the nock is high and left is because of sight timing or tuning problems which is causing the string to push the nock a little up and to the left. The arrow eventually stabilizes, but is now in this nock high left flight attitude. Without the benefit of the fletching to correct it, it will remain in this attitude. This attitude is causing a lot of drag because the arrow surface area is wind planing.

To correct this we will added a half twist to either the top or bottom cable(s). Shoot a couple of arrows at the target. Compare these arrows to the reference arrow, if the nock is lower then you are on the right track if the nock is higher you are on the wrong. If you are on the right track, added another half twist to the cable and shoot the arrow again until it becomes level. If you end up with an arrow is either a little high or a little low, keep the slightly high setting. It is better to go over the launcher than through it.

To correct the left-right flight we will added a half twist to the left side of the split cable(s). If you are using a shoot through then add a half twist to each of the left cables. Keep shooting and twisting until the arrow is gong straight into the butt.

The next part of this tuning is to group tune the shafts. This would be best done with a Hooter Shooter, because your results will vary with your skill level. Assembling the arrow by float tuning may to some degree make this tuning method unnecessary, but if a consistent flyer is found it can be correct to some degree based on the shooter’s expertise.

I would use several targets during this procedure. I prefer the NFAA single spot target. Start at 10 yards and shoot a couple of arrows. If they seem to be in a common group remove them and set them aside. Shoot a couple of more. If they impact in the same holes as the first two, set them aside also. If one is out, shot it again. If it consistently is impacting away from the others set it off by itself. Continue shooting the arrows until you have separated the ones which group together from the one which don’t.

Now, move the nock on one of the non-grouping arrows by turning the nock a quarter of a turn. If it come into the group then set it with the others, if it doesn’t turn it another quarter and continue shooting and turning the nock until it does. If it refuses then change the nock and try again.

Now, more to 15 yards repeat this shooting and rotating the nock until you have all the arrows grouping. At this distance you should move the nock only about an 1/8th of a rotation. Finally, move to 20 yards and repeat this process this time rotating the nock about a 1/16th of a rotation.

If you are a reasonable shot, this process is quite amazing. You will almost want to forget fletching arrows. But, fletched arrows do work better. Once you have established the nock position, mark the shaft with a permanent marker. Use this mark as a reference for you cock feather when fletching.

Float Tuning

Float tuning is a process to determine the heaviest part of an arrow, which in turn is the stiffest part. This is done by construction of some plugs and floating the arrow shaft in a pan or bath tube to determine this high spot.

The easiest plug to construct by using a small wooden dowel. Chuck the dowel in an electric drill and rotate it on a flat sheet of sandpaper or file to produce a taper. Insert the finished plug into each end of the arrow shaft and then float the arrow shat in the tube. Spin it several times and determine the side which come up the most often by looking at the label. Mark the shaft at the nock end with a small dot and align the nock to it. Your results will vary from shaft to shaft some will have a definite high spot and others will have a best 3 out of 5.

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nuts&bolts

· #7 · Aug 18, 2006

jtb1967 said:
Last night I shot a bareshaft at 30 yards. It was within the 4" bullseye with my three fletched shafts, but the nock end was kicked to the left unlike my flecthed shafts which were straight. Should my bareshaft be straight at 30 yards or is this all I can expect at this distance?

jtb1967:

A bare shaft has zero steering correction.

Therefore, any form flaws will show up,
so if you bow hand is not completely relaxed,
and you maybe torqued the bow slightly,
then the bareshaft may not stick in the target straight.

More likely,
the arrow stiffness is not correct.

If the bareshaft stuck into the target perfectly level,
but the nock was kicked over to the left.....

try this experiment.

Add one full turn to the top and bottom limb bolt.
Fire a few bareshafts if you have them at a comfortable distance.
If 30 yds is comfortable for you, then that's even better.

If the arrow is even worse, more left,
then try the other direction on the limb bolts.

Take off the one full turn on both limb bolts
so you are back at the original starting point.

I like to put a dot of white paint or nail polish
at the 12-o'clock position of both limb bolts,
so I can keep track of where I am.

Now that your limb bolts are back the original position,
take another full turn off both limb bolts.

You are adjusting the draw weight up and then down
to see if that has any effect on the bareshaft flight.

It works, as long as you have good technique,
and good form.

When you can get the right draw weight
so that a bareshaft sticks into the target straight,
then your fletchings have less steering correction work to do,
and your groups will be that much better.

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nuts&bolts

· #11 · Aug 18, 2006

rwphilli said:
I'm using an ICS 340 with a 70lb Allegiance at 30" draw, so the shaft "should" be o.k. My limbs are maxed out already, but I may try backing them off slightly to see if that helps the bareshaft fly any straighter.

rwphilli:

If you are using the Allegiance with speed modules
and a 80% letoff, the ICS 340 shafts are too weak,
assuming a 30" shaft and 100 grain field points.

With 80% letoff, and the Allegiance at 70 lbs of draw weight,
and a 30" shaft, with 2" blazer vanes and a 100 grain field point,
the appropriate draw weight = 50 lbs.

With 65% letoff, and the Allegiance at 70 lbs of draw weight,
and a 30" shaft, with 2" blazer vanes and a 100 grain field point,
the appropriate draw weight = 55 lbs.

If you switch to ICS 300 shafts

With 80% letoff, and the Allegiance at 70 lbs of draw weight,
and a 30" shaft, with 2" blazer vanes and a 100 grain field point,
the appropriate draw weight = 62 lbs.

With 65% letoff, and the Allegiance at 70 lbs of draw weight,
and a 30" shaft, with 2" blazer vanes and a 100 grain field point,
the appropriate draw weight = 67 lbs.

So, the bareshaft is telling you
that the shaft is too weak for 70 lbs of draw weight
and a 30" draw length for your current arrow shaft length.

Drop the draw weight,

and if possible, shorten the arrow shaft (say 1/4-inch or more)

and go to a lighter field point (say 85 grain field point)

and add an arrow wrap (full sheet 7-inches long, weighing 10 grains)

and use the largest vanes you can find (say 4-inch vanes).

All of the above will stiffen the shaft.

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nuts&bolts

· #13 · Aug 18, 2006

jtb1967 said:
nuts&bolts,

My shafts are currently 29" and I'm using a short wrap with 2" Blazer vanes and a 100 grain point. I'd think a lighter tip might make my FOC a little on the light side. I may pick up a couple 300 shafts and give them a try though.

Hey there jtb1967:

The Beman ICS 300 shafts will work perfectly for you
at 70 lbs of draw weight and a 29" shaft length
(not including the nock or insert)

and assuming a short arrow wrap with 2-inch Blazer vanes

and 100 grain field points or broadheads.

Assuming speed modules as 80% letoff....
your sweet spot should be around 66 lbs of draw weight

estimated velocity 304 fps
6.417 grains per lb of draw weight
FOC = 10.46%
86.81 lbs of KE

Assuming speed modules as 65% letoff....
your sweet spot should be around 70 lbs of draw weight

estimated velocity 314 fps
6.05 grains per lb of draw weight
FOC = 10.46%
92.62 lbs of KE

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nuts&bolts

· #15 · Aug 18, 2006

jtb1967 said:
I appreciate the help. I'll try a couple 300's, but they'll have to work at full poundage. I used to shoot 86 lbs and I'm down to 70 lb with middle age. I'm not willin to hit the 60 lb range for at least another 10 years!

I'm actually only getting 302 fps with the 340's at 70 lbs. That's more than enough speed, but I'm kind of in love with that 300 fps barrier.

Just swap in some 65% modules
and you get blazing speed at 70 lbs of draw weight.

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