[attachment=1,msg2793115]
The bare shafts in the above photo were shot from the same bow with the same configuration: a 47# takedown recurve with the nock placed at 5/8" above square. This is not just a random grouping. I shot many times with each bare shaft, and the above grouping is representative of the way each bare shaft hits. The top two are 5575 GT, the top one cut to 30" and the bottom one to 29". Both have the same spine, as closely as I can measure. Two of the bottom three are 3555 GT, and the black one is a GT 500. All are cut to 29". The 3555 that is more horizontal is stiffer than the one that is more nock high, and the 500 is slightly weaker than the 3555's. All bare shafts have 145 grain points.
The nock right, nock left variations (not shown) are unremarkable. Stiffer shafts are slightly more nock right than weaker shafts, although nothing like the nock high variations shown. The 30" 5575 is the closest to being centered R/L, but none of them are that far off.
I am puzzled that I get so much nock high/low variation without moving the nock point. Although it is not obvious in the photo, the 5575 cut to 29" consistently gets slightly nock low, the stiffer of the two 3555's consistently gets about 3-5 degrees nock high, while the 30" 5575, the 500 and the other 3555 are consistently 10 degrees or more nock high.
Any ideas on why this is happening would be appreciated.
It's possible that your nocking point is too high and your getting a bounce effect.
I have seen some bow need it as low as 3/16 .
You could play with it and see.
Just a guess. :dunno:
I never thought of getting a bounce effect from the nock point being too high. I always thought a bounce came from too low of a nock point. I don't think I ever tried a nock point less than 1/2". I'll have to play with that.
if i shoot bareshafts with a canted bow (right handed) a weak spine shows nock high, stiff is nock low. the nock kick is all relative to the cant of the bow and how the arrow flexes around the riser and shelf in my experience. same could be true for false stiff, false weak ect.
This could be true in my case, as the weak ones are nock high and the stiff ones are nock low. That's why I tried 5575's, because the only way I could get rid of nock high with the 3555's was with the one that happened to be stiffer than the others. And the stiffer 5575, the 29" one, is the most nock low of all. I didn't think I was canting that much, but it is a possibility.
[attachment=1]
I shot the same 5 bare shafts again, being careful to hold the bow vertical with each shot. The top and the bottom arrows are both 5575's. The top arrow is 30", and the bottom one is 29". Evidently, the 30" 5575 is the weakest arrow of the group and the 29" 5575 is the stiffest, including the 3555's, based on the left/right deviations. The 30" 5575 also has the highest nock high, while the 29" 5575 has the lowest. The best is the 3555 that is unusually stiff, and I would make all my arrows out of that one, if I could, but it is evidently one of a kind.
I am beginning to think that there is a correlation between arrow stiffness and nock high, although I don't know why that should be.
Quote from: bhylton on April 19, 2018, 09:43:47 PM
if i shoot bareshafts with a canted bow (right handed) a weak spine shows nock high, stiff is nock low. the nock kick is all relative to the cant of the bow and how the arrow flexes around the riser and shelf in my experience. same could be true for false stiff, false weak ect.
This is my first thought
Dave,
Do all the nocks fit the same on the string? Some aren't tighter are they?
Two nocking points?
Split or 3 under? 5/8 would be high for me shooting split - I always set up at 7/16.
Do you have a spine tester to confirm each arrow's spine?
Umm, not to get off topic here, but what the heck is that in the doorway in the background???? Or is that a mirrored wall? Anyway, I'm talking about the brown curved looking thing?
Bisch
Sent from my iPhone using Tapatalk Pro
Quote from: Bisch on April 20, 2018, 09:45:42 AM
Umm, not to get off topic here, but what the heck is that in the doorway in the background???? Or is that a mirrored wall? Anyway, I'm talking about the brown curved looking thing?
Bisch
Sent from my iPhone using Tapatalk Pro
think that is wine cork art
Quote from: rraming on April 20, 2018, 09:51:33 AM
Quote from: Bisch on April 20, 2018, 09:45:42 AM
Umm, not to get off topic here, but what the heck is that in the doorway in the background???? Or is that a mirrored wall? Anyway, I'm talking about the brown curved looking thing?
Bisch
Sent from my iPhone using Tapatalk Pro
think that is wine cork art
Well, there's the answer then! If McDave drank all that wine then tried to tune his bow, no wonder those bare shafts are all wonky!!!! [emoji38][emoji38][emoji38]
Bisch
Sent from my iPhone using Tapatalk Pro
QuoteWell, there's the answer then! If McDave drank all that wine then tried to tune his bow, no wonder those bare shafts are all wonky!!!!
Bisch
LOL Bisch
I made that about 20 years ago out of some wine corks we had saved. My cat at the time thought it made a good scratching post, so she shredded the bottom couple of feet or so. Oh well, at least she appreciated my art. Ol' cat just wandered off one day and never came back....I miss that ol' cat.
[attachment=1,msg2793234]
Anyway, to continue with the tuning project, the photo above is of 3 5575 shafts. As Gold Tip is wont to do, they all are of slightly different spines. The top one measures 92 on my spine tester, while the bottom two measure 82 and 80. I doubt if those are the actual spines, but at least it gives me a basis for comparison. It seems that the higher the spine, the more horizontal the shaft. In fact, the stiffest spined one on top actually shows a slight nock low orientation, which resulted in the high impact. If only they were spined correctly, that would be the end of my quest, but of course they all show somewhat stiff.
The best spine for the bow is 3555, but I have been unable to get rid of the nock high. I reduce the nock point until I get the nock high orientation shown in the first photo I posted, and then further lowering of the nock point does not have any effect on the nock high.
I was surprised that an over-spined bare shaft, 5575, will shoot flat, or even nock low, but a correctly spined bare shaft will not shoot flat.
In answer to some earlier questions, all the nocks are for the same GT shafts, but I did switch a few back and forth to see if I noticed any difference, which I didn't. I shoot 3 fingers under, and a 5/8-3/4 nock height seems to be fairly normal for 3 under. I use two tied-on nocks: one above and one below the arrow nock. In any event, as I mentioned, reducing the nock height does not reduce the nock high, at least with 3555's. I have an old spine tester which uses a weight and a deflection indicator, which will at least give me relative differences.
The 5575's are not that bad. I probably just have to fool around with the length and point weight some until I find some combination that has acceptable up/down and sideways bare shaft deflection. Either that or try some other brand of shaft.
McDave, sorry for the fun I was having a while ago!!! As far as GT spine consistency goes, from my experience spine testing hundreds of GT shafts, the only way you are going to get closely matched sets is to buy lots of shafts and spine each one, and separate them into close groups. That is what I used to do once I got a spine tester, and saw the difference myself!!! That is the sole reason I quit shooting GT shafts. I felt that, for nearly $100/dz of raw shafts, the QC should be better. It was not uncommon for me to have the weakest and stiffest shafts in a dz be nearly .100" difference, and that was not acceptable to me. The shafts I was using back then (XT Hunter black) also had a definite stiff side, and many would vary around the shaft as you spun it on the spine tester as much as .020". Also, every GT shaft I tested was stiffer than the spine printed on the shaft.
The shaft I changed to is even more expensive, but every single shaft I have tested, from multiple dozens bought at different times, has all been within the same .010 spine range!!!
Bisch
No prob, Bisch! I enjoy the camaraderie on here as much as I enjoy the rest of it.
I think for this particular bow, the "average" GT 3555 shaft is too weak, while the GT 5575 is too stiff. I have one GT 3555 shaft that I stumbled on by accident that is stiffer than average, and works perfectly, but I don't have any others like that one. From my measurements, the new GT 500 shaft is even a little weaker than the old GT 3555. What shaft are you using these days? The only reason I stick with GT is habit, and the fact that I've got a lot of GT inserts and shafts laying around. Plus a lot of GT bare shafts, which now that I think of it may not be doing me much good, because I may be bare shafting with one spine and making arrows with another, even though both are marked the same.
If you are using those 3555's at full length, and they are slightly weak, you should just be able to cut them off a tad bit to make them stiff enough.
I am shooting Easton Axis Full Metal Jackets now. The reason: well, I was given a dz shafts in a trade for a bit of work. I was in a slump at the time, and looking for any change I could find to help make things better. Once I put those shafts on the spine tester and saw how consistent the spine was, making the change was easy. Also, with no scientific proof other than seeing it with my own eyes, I firmly believe I get way better penetration with the skinnier shafts. (Everything I do and set up with this is for hunting. I don't have a target setup and a hunting setup. I just have a hunting setup that I use for everything.)
Also, I don't want to come across like I am bashing the GT's. I shot those shafts for a looooooong time, and I can't tell you how many critters I killed with them. They work, as attested by the thousands of folks who still use them. I am just anal about my setups, and could not deal with the inconsistency!
Bisch
I stopped shooting GT's because of problems with consistency and durability.I still have a half dozen or so that are free for the asking.
Archeryprof-
Sent you a PM re: the arrows.
Thanks,
OkKeith
McDave, you have helped me out in the past. May I suggest you watch Ken Beck's bare shaft tuning on Youtube. Very good demo. You seemed to have covered the bases 2 nocking points etc. He explains why some folks can't tune out nock high. It could be contact with the outer edge of the shelf if it is a little wide. He will explain all the rest and demo a week,stiff,and just right arrow. You have too many variations of shafts for me to keep up with. I would pick what should be the proper spine and work with it. Ken the other one,LoL can explain it much better that I. I have talked with him several times he is a great guy. good luck.>>>--->Ken
Hi Ken, your suggestion is a good one, and I have made the same suggestion to others many times. I attended Ken Beck's class on tuning at the BW factory in Nixa, MO, about 15 years ago, and he helped me tune my first arrow, a 2117, on a brand new BW bow I had just taken delivery of at the beginning of the class. The class was primarily a shooting class by Fred Asbell, but I learned just as much from Ken. I have also viewed Ken's section on tuning on Masters of the Bare Bow 2, and his subsequent videos on YouTube.
I have also used his method to tune as many as a hundred other bows and arrows. The easiest of those to tune probably took me about 5 minutes, and the hardest is probably the one I am currently working on. I knew early on that this bow would work well with a GT 3555, cut to my preferred length of 29", with a 145 grain tip, giving me just over 9 gpp, which is the weight I prefer for hunting. The only problem was that I could never get it below 10-15 degrees nock high, no matter where I put the nock point. For months I just gave up on it, assuming, as you suggested, that it was just some inherent characteristic of the bow. But it continued to bug me, and as I would think of different things, I would try them.
Imagine my surprise when I shot a 3555 bare shaft one day and it flew fine, with no nock high! Evidently this bare shaft is one that I hadn't tried before, that is significantly over spined for a 3555. Since I couldn't find any other 3555's like that, I started experimenting with 5575's, which also shot flat, or even nock low in one case, but of course were too stiff. I had no idea that a change in spine would affect nock high, and I don't recall Ken mentioning this either.
The reason I have posted this confusing array of bare shafts is to find out if anyone can make better sense out of it than I can.
McDave, I have found that you can get away with a lot more from a higher nocking point that if it is just 1/32" too low. I use 5/8" as my starting point but often find my height settled at 3/4" (I shoot 3 under). I also have found that I need to raise the nock point just a bit for a larger diameter arrow. I have had my bow well tuned height wise for a quarter inch diameter arrow and then when I shoot a 5/16" arrow I get nock low with the arrow shooting higher.
I have come to the conclusion that just as with tuning for spine, I must tune my bow for nock height or at least check it when changing brands or other dynamics of arrows.
Could spine impact nock height reaction? I think so --- sometimes.
Hi McDave, I knew you were well versed in tuning so I hesitated to reply. After that I saw someone had posted Ken Beck's tuning videos on another thread,and thought whoops. With me it is sometimes the simplest thing I have overlooked. I noticed in the pictures a shaft with the quills on it didn't know if they all did. I sure would like to see the quills smeared with lipstick to see if they contacted the outer edge of the shelf. If so rounding the shelf edge or raising the rest/point of contact would do the trick. Otherwise if the bare shafts and fletched shafts grouped together out to 20 yards or more,I would just forget about it. Oh yes do you shoot 3 under or split? >>>----> Ken
John, I'm aware that nock high caused by too high of a string nock isn't really a problem. In fact, my mentor Rick Welch uses nock location more for fine tuning his POI than for tuning the arrow. I know the nock was high enough for shelf clearance, but for me, it was more of a pride thing: I just couldn't understand why I couldn't get the bare shaft any more level than 10-15 degrees nock high.
Ken, when I decided to go ape-$hit on this, I tried every bare shaft I could put my hands on, some with and some without trimmed feathers. They all reacted similarly: the ones that measured 65 or lower on my spine tester had persistent nock high, while the ones 75 or higher shot level, or even nock low in one case. So while I agree with you that lipstick application is a good idea, I don't think that quill contact was a factor in these tests. I shoot 3 under with two tied on nocks.
This is my current theory, without much of anything to back it up. Normally, we associate fish-tailing with spine issues, and porpoising with nock issues. Normally the world does seem to work that way. However, I don't think the world is quite that simple. In some cases, at least, I think spine issues can result in both fish-tailing and porpoising. In the case of this bow, spines below 65 seem to produce enough porpoising to cause a bounce, that limits how low the nock can be placed. At spines of 75 and above, this doesn't seem to happen. A spine of exactly 75 seems ideal for nock placement, but results in a slight nock right, or stiff indication. Perhaps there is a spine that would be perfect for both, but I have a limited number of bare shafts to test with. (Note that these spine readings are from my old fashioned spine tester and may not be accurate; I wouldn't have thought that a 3555 would be spined at 65-75#).
Well I am just like you in that I have to know the answer. I know it best to move on and advise others to but I can't either. Sorry I couldn't help. I would try a stick on rest to satisfy my own mind. Other that that you seem to have tried everything and I am stumped. Please let me know how it works out. Good Luck. >>>----> Ken
A stick on rest is a good idea. I don't want to use a stick on rest, but it would be interesting to see what effect it has on the persistent nock high issue.
McDave, sounds like you've got a tough one. It would seem there's some unbalanced vertical forces/movement somewhere. Is tiller positive (or equal)? Maybe reverse top/bottom limb positions. I had a bow once with negative tiller that reversing the limbs, corrected the nock high. Assuming no tiller adjustment on the Bob Lee, and consistent bow hand placement (one pivot point), maybe try walking the string to effectively affect tiller and see if the problem goes away. Or put a heavy limb tip protector on either top or bottom limb to affect limb rebound speed/timing.
Maybe vary bow grip pressure point to high wrist (single contact point) vs. low wrist (multiply contact points).
And maybe that stick on rest (maybe a feather rest) will dampen the unbalanced vertical forces.
That's all I have to suggest. Good Luck, hang in there with it....
Hi Tim,
Thanks for your interest. The bow is almost even tiller. I did try reversing the limbs, from maybe 1/16" + tiller to 1/16" - tiller. It did seem to decrease the nock high very slightly, but not enough to really make much difference, so I put them back the way they were. I believe I have consistent hand placement, or at any rate have shot each bare shaft enough times to rule out any anomalies. I will try your suggestions on string walking, high/low wrist, and limb tip protector placement, and the earlier suggestion about a stick on rest, and let you know what happens.
Quote from: Bisch on April 20, 2018, 11:08:11 AM
Quote from: rraming on April 20, 2018, 09:51:33 AM
Quote from: Bisch on April 20, 2018, 09:45:42 AM
Umm, not to get off topic here, but what the heck is that in the doorway in the background???? Or is that a mirrored wall? Anyway, I'm talking about the brown curved looking thing?
Bisch
Sent from my iPhone using Tapatalk Pro
think that is wine cork art
Well, there's the answer then! If McDave drank all that wine then tried to tune his bow, no wonder those bare shafts are all wonky!!!! [emoji38][emoji38][emoji38]
Bisch
Sent from my iPhone using Tapatalk Pro
:laughing: :laughing: :laughing:
In my experience and seriously flawed release and grip, I had to stop bareshaft tuning. I have since started shooting only fletched shafts that I believe are close to what I think I need. I know it is very hard to have this, but if you have a set of say 6 5575's and can trim each one of them 1/2 shorter than the other you'll have a great set of arrows for tuning any future bows. It would be a slight investment up front, but I bet it would solve most of your problems.
As far as the nock high and low, I am able to dictate most of that by hand and finger pressure which is essentially changing the tiller of the bow.
A weird thing is that I used to could bareshaft tune with the best of them. When I got my arrows bare shafted, I knew I was perfect. I believe my release has gone so horrible and inconsistent that I can't seem to string together multiple good shots anymore. That's also a reason I went to shooting fletched arrows.
While I appreciate all of the suggestions made in the last few posts, they are mostly things I wouldn't do other than to satisfy my own curiosity, so would probably end up occupying a dusty corner of my mind while I turned my attention to other projects. However, Ken's suggestion about trying a stick-on rest stuck in my mind (no pun intended). While I don't actually want to use a stick-on rest, I remembered that I have some feather rests I had bought a long time ago and never used. A feather rest brings the arrow up to about the same height as a stick-on rest, and would satisfy my desire to shoot off the shelf. So I tried that, and lo and behold it worked! It reduced the nock-high down to a livable 5 degrees or so with the GT 3555's. Problem solved! Now I can go back to loosing arrows (or should that be losing arrows?).
Years ago I had a lot of difficulty getting rid of nock high on my BW MAII. I spoke to a local well respected bowyer and he told me to raise my brace height about a quarter of an inch. It worked. He told me that the shaft will bend perpendicular to the bow on release as we all know. He said the shaft will also slightly bend parallel to the bow (vertical if you hold the bow straight up and down). This may be why you are getting different angles in the vertical plane. Just a thought
Yes, that is the conclusion I came to as well: the bare shaft was flexing in more than one plane. If I decide not to use the feather rest in the future, I will try raising brace height and see what happens.
A stick on rest with the plastic arm or a feather rest seems to cushion the little bit of vertical shaft flex. I usually always get a little better arrow flight with them. I have a 27 pound wing with a sight pin that I warm up with. I shoot it off the shelf. The first few groups from my regular bow with no sight are always tighter than the bow with a sight. I make both kinds of rests so they are on most of the bows,just never bothered with the warm up bow. Guess I should add a rest or add some sights. :^) I hate that they frown on a raised rest in 3D but i don't get out much anymore anyway. >>>----> Ken
Of course, California is not Texas (does that win the prize for the understatement of the year?), but I don't think any trad 3D tournament here would frown on a feather rest, whereas they would frown on a stick on rest.