Fine Tuning -- the false weak

[deadsilence]

Ive done exactly that in eighths but never anything smaller. Never hit perfect flat flight though. I will try smaller increments.
Thanks

I would guess that you have a false nock-high, which is similar to a false weak, but in this case it is caused by the arrow shaft rebounding off the arrow rest.  It is not always possible to get level bare shaft flight, due to equipment and/or form issues.  In that case, your goal should be to tune for the minimum amount of nock high you can achieve before the shaft starts rebounding off the arrow rest.  So you start really high, maybe 3/4-1” above square, and work your way down in 1/8” increments until you reach a point where you either achieve level bare shaft flight or else reducing the nock height doesn't result in any further reduction in the nock high, and that's where you stop.  I suspect false nock high whenever I see nock high with a nock point of 3/8” or less, although it can occur at higher nock points as well.

Once you know approximately where the crossover point is, you can tune further by moving the nock point in 1/32” increments.  I have seen cases where level bare shaft flight can be attained by moving in 1/32” increments where moving in 1/8” increments missed the sweet spot.

[McDave]

The following form issues can result in nock high:

1.  When gripping the string split fingers, pressing down on the nock with the index finger causes a bow in the arrow shaft which rebounds when the arrow is released, often caused by high string elbow.  The cure is to find a string elbow position that doesn’t result in downward pressure on the nock, and focus on drawing with the back muscles, as drawing with arm muscles can make it difficult to relax the string hand, and thus exacerbate downward pressure on the nock, among a variety of other sins.

2.  When gripping the string 3 under, put most of the finger pressure on the index finger, and very little pressure on the ring finger. 

[deadsilence]

If this makes any difference, the closer I get to a level nocking point the more weak (nock left, right handed shooter) the bare shafts become.

[McDave]

If this makes any difference, the closer I get to a level nocking point the more weak (nock left, right handed shooter) the bare shafts become.

The two are interrelated.  In a nock high bare shaft, the force vector of the shot is not directly in line with the arrow: there is a small vertical force vector in addition to most of the force being directed horizontally.  As that vertical force vector disappears, the horizontal force vector increases.  Since there is more force in the same direction as the arrow, it is like shooting with a slightly more powerful bow, which could give you a weak indication.

The topic of this whole discussion is a false weak spine indication, which has a corollary of a false nock high indication, and both are affected by form issues.  All three of these have to be kept in mind when interpreting the results of shooting a bare shaft.  We are looking for consistency over a number of shots, to eliminate form issues, and an expected direction of change from nock high and nock right/left to center as we change nock height and spine to eliminate the possibility of false nock high or false weak bare shaft indications.  Some of my most puzzling tuning issues have resulted from jumping to conclusions rather than taking the time to shoot a series of different spines and nock heights to ensure that I’m observing “real” rather than “false” bare shaft flight indications.