I've read just about every decent snooker book that has been writen over the last 20 years. Most of them have a section on the nap and how it turns the balls as they travel across the surface of the table.
For those who don't know what nap is, it is cloth used mostly on English style tables that has directional fibres that point toward the rack or black spot end of the table. Commonly refered to as the top of the table.
None of the books I read could explain why nap turn occured the way it does. So about 10 years ago I put my brain into nap mode and came up with an explanation that accounts for all the effects that can be observed. Finally I am putting this out for the snooker loonies to wrap their minds around.
Nap turn should not be confused with swerve, though when shooting up the table with side, the direction of movement is the same.
What astounds people most about nap turn is the effect it has on balls rolling naturally across the surface and even more interesting, is that side (english) on the ball travelling toward the baulk end of the table, turns the cue ball in the opposite direction of what we expect. It turns away from the direction of swerve. eg. Right hand side turns to the left and left side turns to the right. See diagram below.
As my diagram illustrates, the cause of all this is because, the nap fibres, under the weight of the ball, always compress more so toward the top of the table side of the ball.
In shots E,F and G below, we see that a rolling ball always turns toward the top of the table. The reason is that this side of the ball is gripping more firmly to the fibres as more fibres are contacting this side of the ball. A simple comparison would be to roll a rolling pin across a surface with one side of the surface having a layer of sticky grease. The rolling pin will turn toward the sticky side. This is what the cue ball is doing on the nap. Turning towards the high grip side.
To explain the side effect varying up and down the table, we should observe, that a ball with clockwise spin will meet more resistance on the top end of table side than the bottom or baulk end of table side. Therefore it will turn toward 9 O'clock.(Top of diagram) A ball spinning with anti-clockwise spin will be pushed toward 3 O'clock. (Bottom of diagram). (These are determined by looking from above).
Left side shooting up the table is clockwise and left side shooting down the table is also clockwise. Both of these shots turn toward the top of the diagram.
Right side shooting up the table is anti-clockwise as is right side shooting down the table, so both of these shots turn toward the bottom of the diagram.
I hope that is clear enough to understand.
For those who don't know what nap is, it is cloth used mostly on English style tables that has directional fibres that point toward the rack or black spot end of the table. Commonly refered to as the top of the table.
None of the books I read could explain why nap turn occured the way it does. So about 10 years ago I put my brain into nap mode and came up with an explanation that accounts for all the effects that can be observed. Finally I am putting this out for the snooker loonies to wrap their minds around.
Nap turn should not be confused with swerve, though when shooting up the table with side, the direction of movement is the same.
What astounds people most about nap turn is the effect it has on balls rolling naturally across the surface and even more interesting, is that side (english) on the ball travelling toward the baulk end of the table, turns the cue ball in the opposite direction of what we expect. It turns away from the direction of swerve. eg. Right hand side turns to the left and left side turns to the right. See diagram below.
As my diagram illustrates, the cause of all this is because, the nap fibres, under the weight of the ball, always compress more so toward the top of the table side of the ball.
In shots E,F and G below, we see that a rolling ball always turns toward the top of the table. The reason is that this side of the ball is gripping more firmly to the fibres as more fibres are contacting this side of the ball. A simple comparison would be to roll a rolling pin across a surface with one side of the surface having a layer of sticky grease. The rolling pin will turn toward the sticky side. This is what the cue ball is doing on the nap. Turning towards the high grip side.
To explain the side effect varying up and down the table, we should observe, that a ball with clockwise spin will meet more resistance on the top end of table side than the bottom or baulk end of table side. Therefore it will turn toward 9 O'clock.(Top of diagram) A ball spinning with anti-clockwise spin will be pushed toward 3 O'clock. (Bottom of diagram). (These are determined by looking from above).
Left side shooting up the table is clockwise and left side shooting down the table is also clockwise. Both of these shots turn toward the top of the diagram.
Right side shooting up the table is anti-clockwise as is right side shooting down the table, so both of these shots turn toward the bottom of the diagram.
I hope that is clear enough to understand.
