Summary: David Alciatore ("Dr. Dave") ILLUSTRATED PRINCIPLES
"Squirt Part I: introduction"
Note: Supporting narrated video (NV) demonstrations, high-speed video (HSV) clips, and
technical proofs (TP) can be accessed and viewed online at billiards.colostate.edu. The
reference numbers used in the article help you locate the resources on the website. If you
have a slow or inconvenient Internet connection, you might want to view the resources
from a CD-ROM or DVD. See the website for details.
This is the first article in a series dealing with "squirt." Squirt, also called deflection or cue
ball deflection, refers to the angular change in the initial cue ball (CB) direction due to an off-
center hit. Diagram 1 illustrates the effect. When the CB is hit off center, to impart English
(sidespin), in addition to the large force in the aiming line direction, there is also a small sideways
force that pushes the CB off line. In other words, the CB does not go where you are aiming. The
squirt angle is a measure of how much the deflected cue-ball path differs from the aiming-line
direction. I prefer the term "squirt" to "deflection," because when talking about a "low-deflection"
shaft, things can be confusing. A "low squirt" shaft produces less "CB deflection" than an average
shaft; but the end of the cue stick, because it is lighter than normal cues, actually deflects more
after impact with the CB (e.g., see HSV A.109). So a low-squirt shaft produces smaller CB
deflection, but it results in larger cue stick deflection. That's why I think the term "deflection" can
be confusing when discussing cue sticks.
large cue force