Energy lost to the environment means it went there. I'm done with you. You are acting like a troll. GO READ and learn something.
Is there a logic to choosing shaft diameter? (newbie)
- Thread starter azsportpilot
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Energy lost to the environment means it went there. I'm done with you. You are acting like a troll. GO READ and learn something.
No. That would be much flatter than most people prefer their tip.
No. Both (especially a dime) are much more curvy (i.e., smaller radius of curvature) than the CB.
Regards,
Dave
Energy doesn't just "go there" (wherever you think "there" is). It does something. What does it do "there"?
pj
chgo
PJ,
This "interaction" doesn't seem very helpful or productive. Why do you continue?
Regards,
Dave
One of my team mates just bought a new cue. He keeps saying that he gets so much more spin from his new LD shaft compared to his old Maple shaft. My guess is the difference is the new soft tip on his new cue compared to the 25 year old rock hard tip that was on his Maple cue.
This is only a guess but maybe due to the different shaft diameters people actually are not hitting the same spot on the cue ball with the 2 different diameter shafts. If you are lining up the outer edge of the shaft relative to the outer edge of the cue ball the smaller diameter shaft will actually contact the cue ball farther from the cue ball center line. I realize that everyone refers to "tips of english" from the center line of the cue ball but sometimes our eyes and brain play tricks on us, maybe some people actually look at the miscue limit by judging where the tip is relative to the outer edge of the cue ball.
I think common sense, science, and Dr. Dave proves to us that cue ball spin is not relative to shaft diameter, after all even a dime radius tip is quite a bit larger than 13mm so the tip really does not know the diameter of the shaft behind it.
This is only a guess but maybe due to the different shaft diameters people actually are not hitting the same spot on the cue ball with the 2 different diameter shafts. If you are lining up the outer edge of the shaft relative to the outer edge of the cue ball the smaller diameter shaft will actually contact the cue ball farther from the cue ball center line. I realize that everyone refers to "tips of english" from the center line of the cue ball but sometimes our eyes and brain play tricks on us, maybe some people actually look at the miscue limit by judging where the tip is relative to the outer edge of the cue ball.
I think common sense, science, and Dr. Dave proves to us that cue ball spin is not relative to shaft diameter, after all even a dime radius tip is quite a bit larger than 13mm so the tip really does not know the diameter of the shaft behind it.
CJ Wiley has stated that he varies the prefered size of his tip for different size tables. The larger the table the smaller the tip.
He has a logical reason that I understand but I'll leave it for him to explain.
I doubt his answer will matter to very many, as he plays a different type game.
There is usually much talk about differences in spin regarding tip size but there is also a difference in the level of 'squirt'.
Best 2 All,
Rick
He has a logical reason that I understand but I'll leave it for him to explain.
I doubt his answer will matter to very many, as he plays a different type game.
There is usually much talk about differences in spin regarding tip size but there is also a difference in the level of 'squirt'.
Best 2 All,
Rick
It is true that an LD shaft cannot really impart more spin than a non-LD shaft; although, there are logical explanations for why some people might think this is the case. For more info, see:One of my team mates just bought a new cue. He keeps saying that he gets so much more spin from his new LD shaft compared to his old Maple shaft. My guess is the difference is the new soft tip on his new cue compared to the 25 year old rock hard tip that was on his Maple cue.
This is only a guess but maybe due to the different shaft diameters people actually are not hitting the same spot on the cue ball with the 2 different diameter shafts. If you are lining up the outer edge of the shaft relative to the outer edge of the cue ball the smaller diameter shaft will actually contact the cue ball farther from the cue ball center line. I realize that everyone refers to "tips of english" from the center line of the cue ball but sometimes our eyes and brain play tricks on us, maybe some people actually look at the miscue limit by judging where the tip is relative to the outer edge of the cue ball.
I think common sense, science, and Dr. Dave proves to us that cue ball spin is not relative to shaft diameter, after all even a dime radius tip is quite a bit larger than 13mm so the tip really does not know the diameter of the shaft behind it.
getting more spin with an LD shaft
Enjoy,
Dave
I'm not sure I agree with the explanation given there. I could be wrong, but hear me out.
In this diagram from the link, the force vector is shown to be the same whether using an LD shaft or not. (On edit, when I wrote this I didn't realize the diagram's vertical corresponded to the direction the ball goes, not the direction of the stroke. See below, but the argument is similar in either case). This may be the case for the first instant that the tip touches the ball, but it is not the case for the total force (i.e. the impulse) imparted by the cue on the ball. The contact takes some positive amount of time, and both the cue and the ball move during this time.
We know that with any shaft, the net impulse for a hit on the right, like this one, points slightly to the left of the direction the cue is pointed: that's what deflection is. We also know that an LD shaft causes less deflection than a normal shaft. This is because the shaft flexes more, so the tip can "get out of the way" of the cue ball. This means two things.
1) The net impulse vector points in a more straight direction than with a normal shaft.
2) The average point of contact is further to the right (albeit slightly).
Both of these would imply a greater amount of torque on the ball from the same magnitude of impulse. There is the question of whether the magnitude of the impulse is actually the same in both cases. I don't know the answer, and I don't see why it would necessarily be, but I also don't see why it has to all work out so that the amount of torque is exactly the same in both cases.
On edit: it looks like I misread the diagram, but the argument is still the same. In this diagram, it looks like vertical corresponds to the ultimate direction that the ball ends up going, not the direction that the cue was pointed before contact. In that case, it is correct that the net impulse will point in the same direction for any kind of shaft. The diagram shows the different kinds of shafts compensating for deflection by adjusting the aim direction.
Which is fine but the problem is that it gives a misleading measurement of how far the cue tip is offset from center. The cue tip offset from center only looks the same in the diagram because the diagram is in the reference frame where vertical is the ultimate cue ball path. Which means that, with respect to the direction that the cue is pointed (and this is the frame that matters for the the player lining up the shot), you have to hit further outside on the ball to get the same amount of english (or, more precisely, the same amount of torque per unit of net force). So, either way we do the analysis, we end up with more torque with the same cue offset when using an LD shaft.
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I think the diagram is a reasonable depiction of net impulse. The tip stays in contact with the CB for the same amount of time for an LD vs. non-LD shaft (assuming the tip and shot speed are the same in the comparison). During this incredibly brief time (about one thousandth of a second) , the tip does move with the CB a small amount and the shaft flexes a small amount, but the net impulse won't differ among the different cues (assuming the aim is adjusted for squirt to send the CB in the same direction with each cue).
It is true than an LD shaft causes less cue ball deflection (squirt), but the aim is compensated to account for this in the diagram. BTW, more shaft flex is not what causes less cue ball deflection. For more info, see:
what causes cue ball deflection (squirt)
Exactly.
First realize that the diagram grossly exaggerates the squirt (cue ball deflection) differences. In a to-scale comparison, the the cue alignments would be much, much closer (about 1 degree apart for typical LD vs. non-LD equipment, per the info here).
Regardless, your point is valid. With an LD shaft, to get the same amount of spin (i.e., the same effective tip offset), the actual tip offset will be slightly less than with a non-LD shaft (see the diagram at the top of TP B.7 for an exaggerated illustration of this). But the real difference is so slight, I think that for all practical purposes it is negligible. Also, if a shaft had much more endmass (much more than a slight amount more), you would be able to hit farther out on the CB, with a larger actual tip offset, to get the same effective tip offset (and spin) produced with the LD shaft. Therefore, an LD shaft cannot produce more spin; although, the aim and tip offset will be slightly different to get the same amount of spin. For an extreme example of this, see the video and info on the miscue-limit squirt effects page.
Regards,
Dave
Thanks for the response and the links.
If I am understanding correctly, the term "endmass" means the effective lateral resistance of the cue tip (i.e. the ratio between lateral acceleration and lateral force, the "m" in F=ma). But the endmass doesn't come from actual mass, at least not primarily, which means that it seems to me that it is the flexibility of the cue is what mainly determines the effective endmass, which in turn determines the amount of squirt. Am I missing something?
OK, so you do get more english for the same actual tip offset, but the increased endmass allows you to hit further out because the effective offset will be less than the actual offset. Which means that the maximum english is still the same, which makes sense -- one would think the maximum is determined by friction, which limits the ratio of torque to central force.
I guess the only possibility left for any "maximum english" effect is if you take into account the possibility that you don't hit the ball at exactly the point where you line it up, but instead somewhere random in the nearby vicinity. Judging (crudely) from that diagram, it looks like the effective offset is more sensitive to changes in the actual offset for a higher-deflection cue, so arguably, the amount of english you can "safely" get might be higher with an LD shaft, simply because you can get closer to the limit without risking a miscue. There's also an argument that maybe LD allows you to be (very slightly) more accurate with the amount of english that ends up on the ball. But like you say, the actual angles are much smaller than in the diagram, so it probably doesn't make any noticeable difference in practice.
If I am understanding correctly, the term "endmass" means the effective lateral resistance of the cue tip (i.e. the ratio between lateral acceleration and lateral force, the "m" in F=ma). But the endmass doesn't come from actual mass, at least not primarily, which means that it seems to me that it is the flexibility of the cue is what mainly determines the effective endmass, which in turn determines the amount of squirt. Am I missing something?
OK, so you do get more english for the same actual tip offset, but the increased endmass allows you to hit further out because the effective offset will be less than the actual offset. Which means that the maximum english is still the same, which makes sense -- one would think the maximum is determined by friction, which limits the ratio of torque to central force.
I guess the only possibility left for any "maximum english" effect is if you take into account the possibility that you don't hit the ball at exactly the point where you line it up, but instead somewhere random in the nearby vicinity. Judging (crudely) from that diagram, it looks like the effective offset is more sensitive to changes in the actual offset for a higher-deflection cue, so arguably, the amount of english you can "safely" get might be higher with an LD shaft, simply because you can get closer to the limit without risking a miscue. There's also an argument that maybe LD allows you to be (very slightly) more accurate with the amount of english that ends up on the ball. But like you say, the actual angles are much smaller than in the diagram, so it probably doesn't make any noticeable difference in practice.
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You're welcome.
The what causes squirt resource page does about a good of job explaining it as I can, especially with the high-speed video images. When the CB starts to rotate during tip contact, the CB pushes the tip to the side. The force required to do this is directly related to the amount of mass moved (the shaft endmass), because mass has inertia which requires force to accelerate. The amount of shaft flex is very small at this point. The sideways force exerted by the CB on the tip results in an equal and opposite reaction from the tip back on the CB. This is why the CB deflects (squirts) sideways some. In simple terms, if the CB pushes sideways on the tip, the tip pushes back. I hope that makes sense. The following article might help in understanding how it is the mass (and not shaft flex) that creates squirt):
"Return of the squirt robot" (BD, August, 2008)
Bingo!
Agreed.
Regards,
Dave
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