# Bare shaft tuning



## jim p (Oct 29, 2003)

I have a single cam bow that the bare shaft is hitting tip low or tail high. I have moved the blade rest so that the arrow is in the center of the berger hole. I have moved the d loop down the string and the arrow still hits tip low. 

So I moved the d loop up so that the d loop is about 1/8" above level. Now the bare shaft hits straight into the target but it is about 5" below the fletched arrow.

So what would be a fix for this?

I have thought about using a larger serving on the string at the cam so that the bottom part of the cam will take up string faster. I have used .014" halo on both ends of the string so I could go up to .017" serving on the bottom of the string. Has anyone tried this?


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## nuts&bolts (Mar 25, 2005)

jim p said:


> I have a single cam bow that the bare shaft is hitting tip low or tail high. I have moved the blade rest so that the arrow is in the center of the berger hole. I have moved the d loop down the string and the arrow still hits tip low.
> 
> So I moved the d loop up so that the d loop is about 1/8" above level. Now the bare shaft hits straight into the target but it is about 5" below the fletched arrow.
> 
> ...


Very common for a BLADE rest to cause the TAIL HIGH condition, cuz a BLADE rest is a spring board. Example. Championship level shooter. Shoots 300s on a 5 spot all day, each day of the week. One week before the MidWest Open championship, last year, he shoots a BARESHAFT to see what happens at 20 yards.



What is happening? Well, first problem was he was using a 0.010 blade. BUT BUT BUT, that's what the blade manufacturer says to use. You figure BLADE thickness based on WEIGHT. right? Well, short answer NO. You figure BLADE thickness based on RESULTS. So, this championship level shooter, was not getting the RESULTS he wanted. He wanted a HIGHER x-ring count. Cuz, well, DUH, he wanted to win. So, how do you fix that NASTY tail high BARESHAFT arrow flight? Well, let's see his CURRENT setup, that was NOT getting him the RESULTS....Darn, there's that word again... let's see the setup that was NOT getting this shooter, the X-COUNT that he wanted.





Bow at rest. Check. Arrow is level with the 0.010 blade, recommended by the BLADE manufacturer. CHeck..NO, WRONG. IF you have a blade ANGLE and if you have a BLADE stiffness (blade TOO THICK) that the arrow is fully supported by blade, meaning you have ZERO sag at rest, THIS is your problem. 

STEP 1. Set blade angle to 30 degrees. TAke away your backer blades. Start with the thinnest blade, the 0.008. BUT BUT BUT, this guy is using FAT carbon tubes, BUT BUT BUT this guy is probably using heavy target points. Yeah, so what. Remember, we are doing DETECTIVE work, and we are looking to BOOST x-count. FORGET what you THINK you know, and let's see if we can get rid of that NASTY tail high arrow flight. BUT BUT BUT, I don't have a way to figure 30 degrees. Fold a paper triangle. Bottom of triangle is 1.75-inches. Vertical leg of triangle is 1-inch. Angle is 30 degrees. 



STEP 2. AFTER you tune the blade angle to 30 degrees, then, we put your bow SIDEWAYS on a table, workbench, the floor. ANY flat surface. WHY put your bow SIDEWAYS? To kill the effects of gravity. WAnt zero load on the blade, when setting blade arrow rest height. GEt the arrow 90 degrees to your bowstring. GEt the arrow parallel to your target sight extension arm. DROP the blade rest all the way down, bottom of the vertical adjustment range, to get the blade OUT of the way.





STEP 3. Arrow is now at 90 degrees to your bowstring. SImple sheet of paper is an excellent reference for 90 degrees. Corners of a sheet of paper are PERFECTLY 90 degrees. So, now move the arrow rest vertical micro adjust knob, move the arrow rest UP closer and closer to the arrow. WE want the arrow to just KISS the blade tips, with ZERO bending on the blade. THIS is why your bow is sideways on a table...or the floor.



ALMOST there. MOVE blade rest EVEN HIGHER.





CONTACT. Blade notch is in full contact with the arrow, and there is ZERO bending on the blade. THIS is how to get the blade arrow rest vertical position, to an EXCELLENT starting position, within THOUSANDTHS of an inch. SERIOUSLY. NOT kidding. THIS position is accurate to several THOUSANDTHS of an inch. YES, tuning a blade rest is THIS picky.


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## nuts&bolts (Mar 25, 2005)

THIS is how it looks, when you are done, setting the STARTING vertical position for the blade arrow rest. BUT BUT BUT, what happens when the bow is now vertical. SAG. YOU want SAG...LOTS of SAG.



BUT BUT BUT, how could that POSSIBLY work? BLADE is too thin. ARrow is going to DRIVE into the ground. No. Basic aerodynamics. The vanes provide LIFT... a tremendous amount of LIFT. When you launch your arrow the VANES will DRIVE the front pointy end of the stick to LEVEL arrow flight, assuming a LEVEL front stab and a LEVEL, shoulder height x-ring. So, WHY the BLADE SAG? The blade is a simple leaf spring suspension, a crude shock absorber. So, when you dial in BLADE SAG...enough SAG, you fine tune the dampening, you fine tune the CALMING effect on the WILD bending in the middle of the arrow, when you LAUNCH an arrow. SO, what happens when you do this CRAZY setup procedure?

THIS happens.



I had to dial in another 0.004-inches of VERTICAL adjustment, and I got this result. I have a micro adjust BLADE rest and two clicks moves the arrow rest down about the thickness of a sheet of paper. Group size dropped nearly in half, with this TINY adjustment. BIG deal. That's just YOU. Well, it works for OTHER folks as well.



He ground the sides of the 0.008 inch blade to FURTHER weaken the blade. He USED to blindly follow the usual instructions about BLADE thickness and arrow weight. NOW, he discovered how a blade, leaf spring suspension REALLY works. So, he went to a super FLAT blade angle, to further WEAKEN the dynamic SPINE reaction of the blade, the 0.008-inch blade. Then, he bent the tips, to provide vertical clearance for his vanes. Then, he further weakened the blade by machining the blade edges/sides. So, how about the RESULTS????

I have a stress test I use for my students. TAKE one fletched arrow and try to FIRE that ONE arrow into the SAME hole...thirty times. MOST of my students do this at 2 yards or 3 yards, and some do it at 5 yards and SIX yards. NOT this guy. He did my STRESS TEST at the full TWENTY yards.



ONE fletched arrow fired TWENTY-ONE times, into a SINGLE HOLE, at 20 yards. BAM. RESULTS based tuning. PS. He won his age class at the Mid West Open, last year.


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## nuts&bolts (Mar 25, 2005)

jim p said:


> I have a single cam bow that the bare shaft is hitting tip low or tail high. I have moved the blade rest so that the arrow is in the center of the berger hole. I have moved the d loop down the string and the arrow still hits tip low.
> 
> So I moved the d loop up so that the d loop is about 1/8" above level. Now the bare shaft hits straight into the target but it is about 5" below the fletched arrow.
> 
> ...


I have an Apex 7, single cam. The single cams are EXTREMELY sensitive to cam rotation position. Work the bottom end loop of the buss cable, and experiment with half twist removed, experiment with half twist added...try 1 twist removed, try 1 twist added, to change the the cam starting rotation position. This has a large effect on level nock travel. TYPICAL for the d-loop to need to be moved higher, on a single cam to get level nock travel. Also, I need to weaken one limb bolt, to get even closer to level nock travel for a single cam. Ultimate test for LEVEL nock travel. 20 yards. FLETCHED and bare.





so, you have a double whammy. Single cam bow AND a blade rest, both combine to give you TAIL high bareshafts. Final step to try. GRIV Torqueless loop.



Gotta set the tied nocking points on a draw board. MUST have the bow at full draw, to figure out where to put the top tied nocking point. PUT the lower tied nocking point on the center serving. GET the bow to full draw, and then, mark the top of the nock, with a strip of masking tape. Even with my 40-inch ATA bow, the tied nocking points end up double the height/thickness of my Beiter Asymmetrical nocks. MUST use nocks with REALLY LONG ears, to prevent nock pinch. If you use short ear nocks, and a Torqueless Loop, you WILL DRY fire your bow. The GRIV Torqueless loop was the FINAL step for me to get LEVEL bareshaft flight, and tight groups...with a BLADE rest.


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## jim p (Oct 29, 2003)

Thanks. It looks like there are a few ways to get better arrow flight.

My total arrow weight is 305 grains and I am getting about 1/4" sag. I think that the blade is a .008" narrow blade. I may grind it down some and see what happens.

I am wanting to use this as a hunting bow later so I am considering putting a drop away rest on the bow. I just wanted to see how it would tune before I went and changed the rest. This bow will be a hunting bow so I could get by with only sighting in for broadheads and hunting. But I like to think that my equipment is working as well as possible.

I may also try a p loop like the torqueless loop to see how this affects the arrow flight.

The tiller of the bow is set at zero for now so both limbs are pretty much equal in poundage.

I don't really know where the cam rotation starting point should be. So adjusting the buss cable will just be a trial and error operation.


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## jim p (Oct 29, 2003)

It looks like the p loop may get the bow to tune. I am going back out and do a little more testing and fine tuning. I am going to have to move my peep down because the p loop is much lower than the d loop which is changing my anchor.


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## nuts&bolts (Mar 25, 2005)

jim p said:


> Thanks. It looks like there are a few ways to get better arrow flight.
> 
> My total arrow weight is 305 grains and I am getting about 1/4" sag. I think that the blade is a .008" narrow blade. I may grind it down some and see what happens.
> 
> ...


Just play with it. FOR me, on my apex 7, I tried adding twists, I tried removing twists, but I get the BEST results (smallest high-low miss pattern) with the Apex 7 timing dots dead parallel to the bowstring, like Mathews recommends.



Now, this did not get me LEVEL bareshaft arrow flight, getting the Apex 7 timing dots parallel to the string, just got me the SMALLEST high-low miss pattern. I ended up with a slightly higher d-loop and working ONE limb bolt weaker than the other. BUT, the blade rest would always give me a TAIL high bareshaft. So, finally stumbled on the GRIV Torqueless loop and that was the answer. BUT, I had to make 4 versions (each a different length) to dial out horizontal misses. When you finally dial in a BLADE rest, the results are Amazing.


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## jim p (Oct 29, 2003)

It looks like the p loop moved the arrows to within 2" of each other but now the bare shaft is now diving nose low again.

I am using a .008" narrow blade.

I can move the p loop nocking point up and maybe the bare shaft will again start going straight into the target.


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## nuts&bolts (Mar 25, 2005)

jim p said:


> It looks like the p loop moved the arrows to within 2" of each other but now the bare shaft is now diving nose low again.
> 
> I am using a .008" narrow blade.
> 
> I can move the p loop nocking point up and maybe the bare shaft will again start going straight into the target.


Remove 1 turn off top limb bolt. I had to do this on my Apex 7.


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## jim p (Oct 29, 2003)

I took a turn off the top limb and the bare shaft is now hitting straight into the target but is again 5" low of the fletched arrow.

Since I want to use the bow for hunting, I think that I will stop tuning now and put a drop away on before I do any more tuning.

It has been interesting seeing how the bare shaft responds to the changes. I didn't realize that single cams and spring rests were a tough combination to tune.


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## TRUE HUNT (Nov 8, 2006)

Tag for target bow.


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## nuts&bolts (Mar 25, 2005)

jim p said:


> I took a turn off the top limb and the bare shaft is now hitting straight into the target but is again 5" low of the fletched arrow.
> 
> Since I want to use the bow for hunting, I think that I will stop tuning now and put a drop away on before I do any more tuning.
> 
> It has been interesting seeing how the bare shaft responds to the changes. I didn't realize that single cams and spring rests were a tough combination to tune.


One of the hardest combos, due to nock travel issues with the Single cam. Since single cams ONLY come with ONE size of idler wheel, but, you have a WIDE range of cam sizes...there is only ONE draw length size, that will work BEST with that ONE idler wheel diameter. When the cam size is TOO SMALL or TOO LARGE, you get nock travel issues. The FIX for nock travel on a single cam design, is to have a DRAW Length specific IDLER wheel for EACH fixed draw length cam size. But, due to COST, you will never ever see this happen.


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## jim p (Oct 29, 2003)

I got it dialed in.

I used a p loop and made sure to have the tied in nocking points far enough apart to not have any nock pinch.

My bare shaft was hitting right of my fletched arrows. I tried yoke tuning and moving my rest with little results. I decided to put a little lean in the top wheel and to put my rest back to 7/8" which is pretty much center shot. When I did this my bare shaft would hit straight into the target but about 4" right of my fletched arrow.

So I pull out another tuning trick that N&B told me about adjusting the draw length. I shorten the string by about 5 turns and the bare shaft and fletched arrows are now hitting in a vertical line.

I know that I am tuning backwards but I now go to tune the vertical hits. Again my bare shaft is hitting straight into the target but it is 5" above the fletched arrow. I start turning limb bolts to see if I can get things to come together. This would move both shafts up and down but would not make them come together. I bottomed both limb bolts and decided to move the rest down about 1/64". This did the trick and both shafts started hitting within 1/2" of each other.

The things that seem to be critical to tuning this bow was using the p loop and to adjust the draw length. This has me wondering if the draw length should be determined by bare shaft tuning.

Thanks for all the help.


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## nuts&bolts (Mar 25, 2005)

jim p said:


> I got it dialed in.
> 
> I used a p loop and made sure to have the tied in nocking points far enough apart to not have any nock pinch.
> 
> ...


Yes...BARE SHAFT point of impact give hints about how well the bow DRAW LENGTH fits the shooter...not arrow spine.

BEFORE group at 20 yards, with the bow draw length in spec at 29-inches, using 29-inch draw length modules.



AFTER group size, at 20 yards, with the bow OUT OF SPEC, using 29-inch draw length modules, and growing the brace height 1/4-inch LONGER than spec, by shortening the cables, to grow brace and DL.



No change to the arrow rest sideways position, NO yoke tuning, NO arrow spine change...exact same spine arrows. ONLY change was draw length...by working the cables SHORTER, to grow the draw length longer than spec. Used bareshafts to figure out WHICH direction to go OUT of spec, for draw length.



Bareshaft missed 8-inches LEFT, when aiming at the x-ring. Right handed shooter. NO, this is not a STIFF spine reaction...cuz I am a compound RELEASE shooter. STIFF or WEAK bareshaft reaction is only for FINGERS compound and FINGERS recurve shooters.

So, since I am RIGHT handed, think of a compass needle...your right forearm (release side forearm) is a compass needle. Your RIGHT elbow is in front of your body, when the draw length is TOO LONG...the "compass needle" is pointed NORTH WEST, to your LEFT...if the front stab is pointed DUE NORTH. So, you GROW the draw length....to fix a bareshaft that misses 8-INCHES LEFT....not increase point weight.



1/16th inch LONGER draw length results.



1/8th inch LONGER DL results. See the bareshaft point of impact moving to the RIGHT?



1/4-inch LONGER DL results. Bareshaft is 3/4-inch outside the x-ring.



FLETCHED arrow results with the DL 1/4-inch out of spec. Of course, a shooter can ONLY tune to the skill level of the shooter. So, shoot MULTIPLE bareshafts, to eliminate bad shots. ONLY evaluate the GOOD bareshaft shots, which means, only look at tight GROUPS of bareshafts...and ignore bareshaft fliers.


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## Tracker12 (Sep 22, 2003)

So is the DL change effecting how the bow causes the impact change or the shorter DL is making the archery hit left. Having a hard time grasping that much of a change in impact by a 1/4 DL change. My bow does not have muck of a wall and it is very easy to creep with it. That creep will change my impact but it is usually 1" at 20 yards.


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## jim p (Oct 29, 2003)

Draw length does affect the left and right on a bare shaft.

Now that I got everything tuned, it is time to put on a smackdown and do some more tuning. I was able to put a d loop back on and the vertical tune was easy. My bare shaft is hitting to the right about 2" with a left tail lean. So I need to shorten the draw length a little or maybe try some wheel lean after I make sure that the center shot is at 7/8" or so.

The good news is that we are having mild weather so I can get out and shoot without freezing.


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## RCR_III (Mar 19, 2011)

The way your draw length is set does affect bare shaft impacts. Because it is changing pressure points in the grip. The best method to follow is get your form correct. Then set the draw length of the bow to you. Then adjust the d loop to the correct length. Then use bare shafts to tune the bow to the RIGHT draw length for you. Not the draw length an out of tune bow showed you, you should have. That's likely to have your form not in good positioning if you're not looking after the right aspects.


jim p said:


> Draw length does affect the left and right on a bare shaft.
> 
> Now that I got everything tuned, it is time to put on a smackdown and do some more tuning. I was able to put a d loop back on and the vertical tune was easy. My bare shaft is hitting to the right about 2" with a left tail lean. So I need to shorten the draw length a little or maybe try some wheel lean after I make sure that the center shot is at 7/8" or so.
> 
> The good news is that we are having mild weather so I can get out and shoot without freezing.


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## jim p (Oct 29, 2003)

What is your technique for bare shaft tuning?

Please start with a bow that is out of tune in every respect.


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## RCR_III (Mar 19, 2011)

jim p said:


> What is your technique for bare shaft tuning?
> 
> Please start with a bow that is out of tune in every respect.


I've got a write up I'm working on for this. I wanted to have it out already but I'm wanting to put a video with it too and I've been waiting on the weather. May have to just finish the written part today and post it first. I'll send you a pm when I do so you can see it.


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## jim p (Oct 29, 2003)

Thanks. I usually go round in circles while I adjust for best performance. For instance, if I tune and end up with a nock left tear a 20 yards, then I know that I need to make a change like shorten draw length. When this is done now the up and down may be affected with a single cam bow. So the vertical gets adjusted.

After a few tips around the tuning block, the adjustments are so small that I can't detect a need for another change.

Today I had a little tail left at 20 yards so I shortened my draw length by wrapping a sock around the grip and the shaft straightened up instantly. So now I need to shorten the draw and take a few more trips around the tuning block.


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## RCR_III (Mar 19, 2011)

That's why tuning the bow and form/draw length is separate. I'll pm u the article. The video may not get done tomorrow with the weather, but you can read what I'll publish when I get the video complete.


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## ohiobbc123 (Jan 21, 2007)

Saved


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## Etheis (Sep 28, 2013)

RCR_III said:


> That's why tuning the bow and form/draw length is separate. I'll pm u the article. The video may not get done tomorrow with the weather, but you can read what I'll publish when I get the video complete.


Totally agree, you can't take a poorly tuned bow and starting changing the draw length and this, that and the other on the persons form to make up for the poorly tuned bow. That being said you can't have horrible form and start changing the tune in the bow to compensate for the persons horrible form or DL within reason.


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## RCR_III (Mar 19, 2011)

Etheis said:


> Totally agree, you can't take a poorly tuned bow and starting changing the draw length and this, that and the other on the persons form to make up for the poorly tuned bow. That being said you can't have horrible form and start changing the tune in the bow to compensate for the persons horrible form or DL within reason.


Absolutely agree. There's an order of operations for sure!


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## jim p (Oct 29, 2003)

I loaned my bow press to a fellow shooter and I not been able to do the final tune on my bow. So the bare shaft is hitting 2" right with a left tail. I decided to shoot a broadhead to see how it would impact. The broad head hit 2" left. Is this typical?

I am guessing that when the bare shaft is in tune that the broad head will also hit on target. I need to try a little more yoke tuning to see if that will bring things together.


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