My thoughts concerning using outside English to "spin balls in," backed up by lots of resources, can be found here:
Outside English (OE) can be used to reduce (and even eliminate) throw and cling, but it can be difficult to judge the amount of English required for a particular cut angle (although, people can get good at this). Also, with English comes squirt and swerve, compensation for which can be challenging (although, people can get good at this). You need to have feel and understanding for many effects when using English. Many (if not all) of them are summarized and demonstrated here:
A case can actually be made that inside English might be a better approach for dealing with throw than outside English. For more info, see:
Outside English can certainly be a good choice when trying to hold the cue ball (sometimes). For more info, see:
Also, if cling is a concern (e.g., with old, worn, dirty balls; or if you are pro, where cling on one shot can mean the difference in a match), then "spinning the ball in" might be a good approach.
Regards,
Dave
Dave, your conclusions seem to perfectly match my recent experiences switching between many different venues with a wide range of dirty/clean balls. However, I wonder if there is one more factor nobody has considered yet... How significantly does OB spin affect the range of angles a pocket will accept a ball at? On a cut shot, where dead center ball is used, the OB obviously acquires CIE. More importantly, this CIE is outside english which in theory could cause balls to "jar" if hit into the pocket facing/horn, where as with no english the pocket might accept the same ball at the same angle. Obviously this effect would only matter for a limited number of situations, particularly in situations where any OB english would not have worn off before reaching the pocket.
This is not directed at Dr. Dave, but to the thread in general: On the debate about spinning the ball in, I also wanted to respond to the argument that squirt/swerve are bigger factors than throw. We know that swerve will probably not be a factor, on a firm hit, so lets eliminate that from the argument for now. This is really about squirt vs throw, and what leads to pocketing balls more consistently. I do agree that squirt CAN have more of an impact on the final trajectory of the OB. However, it's logically unsound (even though it may be true) to conclude that this means squirt is more inconsistent. If we consider what factors determine the amount of squirt (cue stick, amount of english), and what causes throw (friction coefficient of balls), it might make more sense to say throw is more inconsistent. After all, players usually shoot with the same cue regardless of where they are, but rarely do players bring their own balls. A player can learn the squirt characteristics of their cue, but it would be impossible to learn the throw characteristics of all balls everywhere. To add to that, squirt is a factor of the game that players are forced to learn. They may be much better at adjusting for squirt than they are at guessing how sticky a given set of balls is and how much a shot will throw.
Given what I just said, it makes perfect sense to substitute an unknown and unpredictable factor (throw) for a known and predictable one (squirt).
I did say lets ignore swerve for the sake of argument, now I want to discuss that a bit. I think the true answer to the whole spin vs over-cut debate is somewhere in the middle. Some shots should be spun, some should be over-cut. The answer to which is right probably depends on the controlling factors of the shot, such as cut angle, speed and CB to OB distance. On a shot where swerve is going to come into play, I think spinning a ball in is more perilous. I think the same thing on very hard (fast) shots, where squirt is extremely large. There is probably a middle ground somewhere, and it is most likely dependent on how well a player compensates for squirt. So this answer may be different for every player.
One final thought on my theory of how OB english affects the angle the pockets will accept balls at. If we assume the theory is correct, then most likely the english will favour one side of the pocket more, and the other side less than when the OB has no english. For example, in Diag 1 below, if this shot is hit with center cue ball, the long rail side of the pocket should be more favorable (than with no OB english) since the CIE will spin the OB into the pocket. Where as the short rail side of the pocket will spin the OB out of the pocket. Now consider the shot in Diag 2, where hitting the short rail side of the pocket will cause the OB to spin in, and the long rail side will cause it to spin out. In both scenarios, the pocket has effectively "shifted" ever so slightly. Interestingly, depending on the geometry (such as OB approach angle, how the pockets are cut, etc.), the additional range of angles that accept/reject a ball on one side of the pocket due to OB english, does not have to equal the range of angles on the other side. This means that depending on the exact shot, the pocket can be effectively smaller or larger (in addition to shifting as described above).
If you truly wanted to be as consistent as possible using the cut/throw method, then you would want to aim at the center of the effective pocket (after compensating for throw) to give yourself the largest margin of error. I think in a lot of cases it might be easier to simply gear the OB when practical, than to consider how the CIE will affect the angles the pocket accepts balls at. Of course, it's obviously best to know the in's and out's of both methods.
Diagram 1:
Diagram 2:
