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dr_dave
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01-23-2016, 08:00 AM

Quote:
Originally Posted by KMRUNOUT View Post
I haven't read all the stuff on Dr. Dave's site about squirt, but I think he also says that shaft flexibility has *some* effect. I don't know how much effect. It does seem to me like it must play at least some role.
First of all, it is important to distinguish between a cue's stiffness in the axial or longitudinal direction and stiffness in the sideways or transverse direction.

For a cue to be able to hit a CB effectively, it must have significant stiffness in the hitting direction (i.e., it must have a large axial of longitudinal stiffness). That's why any theoretical discussion like "What if the cue were a noodle?" is just downright silly (unless the "noodle" is fat and dry, and is able to resist buckling and fracture during a hit ).

The sideways or transverse stiffness of the cue is much less than the axial or longitudinal stiffness (i.e., the cue is very flexible in response to sideways deflection; and these sideways deflections are very small anyway during an off-center hit, due to the incredibly brief tip contact time). However, transverse stiffness does affect the effective endmass of a shaft and amount of resulting CB deflection (squirt). A complete and detailed explanation of this, supported by numerous resources can be found here:

cue endmass and stiffness effects

Concerning the effects of tip elasticity; theoretically, one would think this would have a large effect on tip contact time and resulting squirt; but in reality, with real tips on real cues, the difference in squirt over a wide range of tip types and hardnesses is miniscule (i.e., of no practical significance). For proof, see cue tip hardness effects and the following video:

NV D.15 - Cue and Tip Testing for Cue Ball Deflection (Squirt)

Enjoy,
Dave

Last edited by dr_dave; 02-22-2019 at 03:38 PM.
  
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