Tuning question

[McDave]

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.

[the rifleman]

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.

[kenneth butler]

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

[McDave]

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#). 

[kenneth butler]

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

[McDave]

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.

[CoilSpring]

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....

[McDave]

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.

[DanielB89]

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


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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!!!!

Bisch


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[DanielB89]

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.

[McDave]

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?).

[Jock Whisky]

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

[McDave]

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.

[kenneth butler]

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

[McDave]

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.