The slow motion video of side spin shows the shaft immediately getting kicked or pushed off its line as soon as it makes contact with the cb, not after. Which means the shaft had to have flexed and deflected right then, allowing the cb to be less affected. It would be the opposite result if the shaft had zero flexibility. Regardless of its end mass, with zero flexibility the entire weight of the cue would pretty much stay on line and push the cb aside. Well, there'd be a little shaft deflection because the hand is soft and cushiony and will allow the shaft to give a little against the weight of the cb, but overall the full weight of the cue stick would influence the cb's deflection a little more.
I realize this is an unrealistic example because no cue shaft has zero flexibility. It's an extreme example to show that flexibility is an absolute necessity to help decrease cb squirt. If two shafts have identical end masses, but one shaft has maxium flexibility while the other has nearly zero flexibility, the amount of cb squirt will surely be different between the two shafts. Where are the experiments that prove or determine when or how the flexive property of a shaft becomes insignificant to cb squirt? In other words, knowing the two extremes, at what stiffness level does a shaft start to really affect cb squirt, despite low end mass? Just curious.
