Tom Simpson © June 2002 – All Rights Reserved – PoolClinics.com
Some shots are harder than they look. One shot that embarrasses all of us is the “straight-in shot.” When the cueball and object ball are lined up straight into the pocket, it sure looks easy. It’s not.
Of course, you have to consider the normal, obvious difficulty factors: how far is the object ball from the pocket, how far is the cueball from the object ball, does the table roll straight, how straight-in is it, and so on.
But there are a couple of factors that are not so obvious, when it comes to straight-ins. The biggest one is the fact that straight in is the angle at which you get the greatest effect from Spin-Induced Throw. Any time you strike the cueball the slightest amount to either side of the vertical axis, you get sidespin (english). OK, OK, we all know this.
When a spinning cueball hits another ball, some of that rotational force in the cueball goes into “throwing” the object ball a little off the course it would have taken if there were no sidespin. This is called Spin-Induced Throw, and it’s an angle change that takes place at the moment of impact. The throw is in the direction of the spin, so for example, if you cut an object ball with a cueball that’s spinning clockwise (left english), Spin-Induced Throw will cause the object ball to be cut as much as a few degrees further to the right than what you’d see if there were no sidespin. A few degrees can make you miss, and the further the object ball is from the pocket, the more that few degrees will matter.
As you shoot thinner and thinner cut shots, the effect of Spin-Induced Throw falls off. Think about how sidespin works when you hit a cushion. If you hit straight into the rail with sidespin, the spin has a large effect on the angle out of the cushion. If you hit the cushion at a thin angle, the sidespin doesn’t do much to alter the angle out. By the same token, the closer you get to straight in, the more effect that sidespin will have on the object ball.
What can we do with this knowledge? The most important thing to focus on when shooting a straight-in shot is hitting the vertical axis of the cueball. Get off that vertical axis even a little bit, and you’d better be making aim adjustments for Spin-Induced Throw, Squirt, and Swerve. They’re all going to happen. Of course, there are lots of times when you have to use english. I’m just saying, on straight-ins, if you use any sidespin, it’s going to have more effect than you might expect.
There’s another factor that makes these shots difficult, and it is not obvious at all. We talked about left & right spin above. The other factor is associated with forward & backward spin (follow & draw). This is not nearly as big a factor, but it’s still a factor. What matters is what the cueball is doing when it hits the object ball – it’s going to be rolling (follow), skidding (stun), or spinning backwards (draw). Whenever possible, try to shoot straight-ins such that the cueball has either follow or draw when it hits the object ball. Here’s the reason: if there is any sidespin, a stunned cueball will cause even more Spin-Induced Throw than a rolling or drawing cueball.
Here’s the summary: Straight-in shots are not easy. To maximize your chances of making the shot, you should aim carefully, take care to avoid unintentional sidespin, and shoot such that the cueball has a little draw or follow when it hits the object ball. Let’s straighten up!