I see lots of evidence, no proof. You did those tests to show an idea of what is happening with most shots. If you want to call that proof, why is there only one shaft ever getting shot with during your videos? There are situations which need to be tested that you haven't tested. You did make note that a closed bridge 'doesn't' have an effect on squirt, but I'm a firm believer it does. No I don't have video evidence, just testimonial evidence from my experience telling me that when I use an open bridge I get more reaction(squirt and spin) out of the cue ball. I wish you wouldn't call one video 'proof'.
The BIG low deflection Hype Campaign.
- Thread starter Kel_82
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I see lots of evidence, no proof. You did those tests to show an idea of what is happening with most shots. If you want to call that proof, why is there only one shaft ever getting shot with during your videos? There are situations which need to be tested that you haven't tested. You did make note that a closed bridge 'doesn't' have an effect on squirt, but I'm a firm believer it does. No I don't have video evidence, just testimonial evidence from my experience telling me that when I use an open bridge I get more reaction(squirt and spin) out of the cue ball. I wish you wouldn't call one video 'proof'.
From your link for one- "Secondly, with a stiffer shaft, transverse elastic waves will travel faster and farther down the shaft (from the tip) during the brief contact time between the tip and ball. The farther the wave travels, the larger the effective "endmass" will be, because more mass is being involved during contact with the ball."
Barioni's testing for another. Also the fact that the same shaft screwed onto different butts will react differently based on the construction of the butt. While agreeing, which I already have, that end mass seemingly plays the largest part, it is not the only aspect otherwise all shafts of similar end mass would give the same test results. (edit).. If this were true than no additional testing would be needed to prove LD than a sample of the end mass.
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The "evidence" is in the video demonstrations and experimental data. The "proof" is in the physics-based analysis (which understandably has too much math and physics for most people).
That's not true for all of the videos and experiments I have done; although, it was true by design where I was attempting to carefully measure the effects of certain things; for example, different tip types and hardnesses on the same high-cue-ball-deflection shaft. But even in that video, I still tested a Predator Z-2 as a baseline. There is also data on my website for a wide range of other cues.
I certainly agree with you there. I can think of several lifetimes of stuff I would like to test if I had enough time and/or enough clones to do the work.
People are free to believe what they want to believe, but I believe that the evidence and theory are fairly clear that the type of bridge has no effect whatsoever on squirt (assuming everything else is the same in the comparison).
Regards,
Dave
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Only the stiffness of the shaft in the "effective endmass" zone (6-8 inches for a typical maple shaft) has an effect on squirt.
I am not familiar with this testing. Do you know of any videos, articles, or websites that document this testing. I generally don't have a lot of faith in anecdotal and secondhand information.
I would love to see convincing evidence proving this is true. If I did, there might be an opportunity to change or improve the current understanding of what causes squirt. Until then, I will remain skeptical on this claim. Based on the physics that goes on during a tip-CB collision, they is no conceivable explanation of why the joint or butt can have any affect (assuming everything else is the same in the comparison).
On this topic, there are many things that can go wrong with robotic testing of cues that can lead to misleading and downright wrong conclusions. For more info, see the robotic squirt testing resource page.
Regards,
Dave
Proof is when evidence can be pointed to and shown that is the cause. You assume a lot of things and have quite a few theories that your using as proof it seems too. And some of those deflection numbers seem quite odd. You took enough time to note nickle vs dime, but didn't bother to test each cue? You have made a substantial claim that the butt doesn't affect the squirt. Is there evidence of this?
You claim that you've put numbers through the wringer and have gotten back supporting evidence that your initial findings are correct. No one else has double checked your work. You make a vast amount of claims that only you seem to be saying.
You have taken other peoples work, which may be wrong itself, and have attempted to compare the data you got to theirs. Some of it matches, some of it doesn't. You'll notice the first thing I said in this thread that achieving a goal of having a listed squirt value is bunk because of all the variances that can go into just one shaft. You have too many tests to perform, that by the time the data is collected, there is no way you can put just one number for a low deflection cue. You can put a range, but then it defeats the purpose of all the testing.
You can say the numbers work for you, but until the public knows these numbers, and is able to comprehend the math behind the calculations. All you have is people screaming that those numbers are wrong. You've been very reluctant to continue your tests when a problem is pointed out, and are very quick to challenge us to do the tests. If you cannot figure out by now, each individual that does a test will come back with different results, means there's more to it than you want to admit.
Please don't insinuate, assume, or say that the numbers when worked on support your claim. They don't. If anything it will lessen the credibility of you in the future. If a true scientist made as many assumptions as you did, they'd be out of a job in a week.
That tidbit about the wave propagation in the shaft changing the effective end mass has me wanting a pernambuco shaft even more... (they use ultrasonic test testing on blanks to determine acoustic propagation speed in pernambuco blanks before using them for violin bows). Although I'm not sure exactly how this would affect how much the shaft flexes in that short period of time (either more or less), and how much rebound it can put back into the cue ball.
I think there is already enough on my website (physics-based analyses, careful experimental results, super slow motion clips, video demonstrations, illustrations, and diagrams) to support the claims. I know you don't consider this "proof" of anything, but I think most people (if they actually looked at and viewed all of the material) would be fairly convinced (and maybe even change their current anecdote-based thinking).
When somebody makes a claim like: "The butt has a direct affect on shaft squirt," a claim that goes against the current understanding of how squirt works, the burden of proof is on the people making the claims. People and companies in the billiards world claim all sorts of things, but that doesn't mean the claims are true.
The comparison of one set of data to another is not that useful in itself if the experiments were done with different procedures and conditions. However, what is useful is the relative comparisons within a single set of experiments. To me, that is of value.
I would agree unless the machine and procedures used to test the shafts were well designed and consistent and followed all of the suggestions on the robotic squirt testing page (for example: level cue, consistent tip shape, size, and hardness, CB test only, etc.). Then the number would be very meaningful, and comparisons would be more relevant.
Catch you later,
Dave
FYI, the force associated with shaft flex is insignificant concerning squirt. It is the sideways momentum change of the endmass that creates the cue-ball-deflection force.
Also, the shaft certainly doesn't rebound while the tip is in contact with the CB.
For more info, see:
what causes squirt
cue deformation and vibration
Regards,
Dave
Dave, you address everything except my last sentence whereby if only end mass is responsible for squirt variations than testing for this would require only the end of the shaft and a comparison of mass. Nothing else would be required if this were 100% true. Are you willing to suggest this it true? This would mean that all shafts with the same end mass have the same deflection characteristics.
The "cutting edge" tip from Buddy Hall
I remember the day Buddy Hall told me "CJ, you don't hit the cue ball with the center of the tip, you play the game with the edge (top/bottom/side) of the tip".
This was a great epiphany for me, and even though I did this naturally (most of the time) it helps to know this type of "uncommon sense".
This is what leads to understanding how to "PIN" your shots. You can tell when buys like Buddy and Efren are playing because their contact (with the cue ball) makes a higher pitched sound.....I've heard comments about this many, many times in my career. 'The Game is the Teacher'
I remember the day Buddy Hall told me "CJ, you don't hit the cue ball with the center of the tip, you play the game with the edge (top/bottom/side) of the tip".
This was a great epiphany for me, and even though I did this naturally (most of the time) it helps to know this type of "uncommon sense".
This is what leads to understanding how to "PIN" your shots. You can tell when buys like Buddy and Efren are playing because their contact (with the cue ball) makes a higher pitched sound.....I've heard comments about this many, many times in my career. 'The Game is the Teacher'
Yes, based on the current understanding of what causes squirt (AKA "cue ball deflection"), shafts with the same "effective endmass" should create the same amount of squirt, regardless of the construction of the remainder of the cue (assuming everything else is the same in the comparison). I haven't tested this directly, but it seems to make sense based on all related tests that have been done. The "hit," "feel," and "feedback" of the cue obviously depends on many things related to a cue's design; but based on the current understanding of what causes squirt, only the "effective endmass" should matter.
I would certainly be interested in seeing convincing evidence that this was not true. If that were the case, there would be more to learn and understand about the physics of squirt. That's always fun.
Best regards,
Dave
lol, and how does one measure 'effective endmass'?
... obviously, with a careful squirt measurement.
Seriously though, for a maple shaft, the "effective endmass" only depends on the last 6-8 inches of the shaft.
You can easily test the claim that a butt can make a difference by first testing a shaft for squirt on a given butt, and then switching the butt with a variety of other butts (or broomsticks, or other objects) and repeating the squirt tests (keeping everything else the same). I recommend the procedure and advice in the following video:
NV D.15 - Cue and Tip Testing for Cue Ball Deflection (Squirt)
No special equipment is required; although, a video camera can be helpful.
With some care, and by throwing out shots that are the wrong speed or are obvious outliers, reasonably consistent and accurate results are possible (especially with the cue as level as possible, with fast shot speeds, and a slick cloth). The results will certainly be reliable enough to answer the question of interest.
If you or anybody else does this, please let us know what you find.
Thanks,
Dave
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I'm going to need a better definition of effective end mass than that...
I mean this isn't quantum physics here. Why don't we just call shaft "color" or "spin" if you're just going to define it based on perceived effects alone.
I mean this isn't quantum physics here. Why don't we just call shaft "color" or "spin" if you're just going to define it based on perceived effects alone.
I'm going to need a better definition of effective end mass than that...
I mean this isn't quantum physics here. Why don't we just call shaft "color" or "spin" if you're just going to define it based on perceived effects alone.
I second that. In one sentence you state that end mass alone is enough to figure out deflection... if every thing else is equal. Well.... which is equal? 6" or 8"? And if neither are equal as one shaft has an "effective endmass", what ever that is, of 6" and another shaft is 8" than simply knowing the weight will not tell you what the deflection value will be. And what if things really are not equal and I have a shaft with an "effective endmass", what ever that is, of 12"?
I don't think that "effective endmass", at least when used by Dave, is a quantity measured in inches. Rather, it would be measured in kilograms, primarily driven by the actual mass of the end of the shaft up to a certain point. At most, that point would be where the transverse wave created by impact travels while the tip is still in contact with the cue ball because anything beyond that does not get a chance to affect the shot. There may be some additional minor effects created by the tip shape/material, but nothing beyond the wave's travel distance during contact should matter when calculating squirt. The rest of the cue could be made of anything (or nothing, I suppose) and the squirt results would not change, although it would affect the "feel" of the cue because the wave continues to travel down to your bridge and grip even after the cue ball leaves the tip. The length of the shaft that factors into the "effective endmass" of the cue would be based on how fast the wave propagates through the shaft material, so it may vary some from one shaft to another, but should be roughly equal for most shafts.
I think that an interesting test of this would be to create a "breakaway" shaft, sort of like the trainer golf club with the hinge in it. If all of this theory holds, you should be able to shoot with such a cue just fine and get the same squirt results, even if it feels terrible.
Since Dave was the one stating it in inches that is what I used understanding that it would be the weight to a certain point behind the tip but thank you for pointing it out.
The idea that the sound wave speed should be roughly equal does not hold water if you are looking to quantify deflection because, as shown by the US Forest Products Lab testing, the speed of sound propagation through Maple can vary considerably. Unless you use this actual speed, along with mass, to compute what deflection is, then the answer is not going to be correct. It is also going to vary with shafts from the same maker so a number obtained in one shaft does not necessarily mean that all shafts measure the same and unless certain parameters in wood preparation are met than the numbers absolutely will vary considerably.
Also, all high (LD) deflection shafts are not built the same. The point(s) that the shaft is bending from would also make a difference as while the last 4" of the shaft might be extremely light the area directly behind that might be extremely stiff.
Once again, the testing done by Barioni, shown here on AZB and ridiculed by most, came to somewhat different conclusions than what is thought to be 'common knowledge'.
Sorry, but the definition of "effective endmass" is not simple. The best I can do is here.
The easiest way to characterize a shaft's endmass is with a simple squirt measurement (for example, as demonstrated here).
To get an actual number for "effective endmass" from the squirt mesurement, you would need to use Equation 13 in TP A.31 - The physics of squirt.
What makes "effective endmass" complex is that mass at different distances from the tip has different effects. As shown in Diagram 4 in "Squirt - Part VII: cue test machine results" (BD, February, 2008), mass closer to the tip has a greater effect than mass farther from the tip. Also, the distance over which mass matters depends on the transverse stiffness of the end of the shaft. For example, a typical carbon fiber shaft would have a longer effective endmass length than a typical maple shaft. For maple shafts, the effective length is about 6 inches.
Now what is clear is that if you want to reduce the squirt (cue ball deflection) created by a shaft, you need to lighten the end closest to the tip as much as possible, and the closer to the tip the better. That's pretty simple.
Catch you later,
Dave
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Ld
I remember Efren saying no LD shafts for me, in a interview called what is in your case in Japan. In the interview Efren talked about how many shafts he brought with him and what kind they were. He had one solid maple, and he had another solid maple shaft being made for him in PI. It also seemed even if Efren did have a problem with a shaft that he could of borrowed one a pretty much shot with any solid maple shaft.
His confidence was in himself and not really into fancy equipment
At that time Efren was world 9 ball champion.
Everyone has to compensate for deflection................
LD shafts are weaker............... because of the reduced mass.
What makes LD shafts better then a normal solid maple ?
What can a LD shaft do that a Solid maple shaft cannot do ?
Solid maple shafts cost less, They are stronger and normally will out live any laminated LD shaft.
The ferrules and joint areas are stronger, and I do not think any glue will hold up like wood does year after year.
LD shafts have less deflection but still have to compensate, JUST like a solid maple shaft.
I remember Efren saying no LD shafts for me, in a interview called what is in your case in Japan. In the interview Efren talked about how many shafts he brought with him and what kind they were. He had one solid maple, and he had another solid maple shaft being made for him in PI. It also seemed even if Efren did have a problem with a shaft that he could of borrowed one a pretty much shot with any solid maple shaft.
His confidence was in himself and not really into fancy equipment
At that time Efren was world 9 ball champion.
Everyone has to compensate for deflection................
LD shafts are weaker............... because of the reduced mass.
What makes LD shafts better then a normal solid maple ?
What can a LD shaft do that a Solid maple shaft cannot do ?
Solid maple shafts cost less, They are stronger and normally will out live any laminated LD shaft.
The ferrules and joint areas are stronger, and I do not think any glue will hold up like wood does year after year.
LD shafts have less deflection but still have to compensate, JUST like a solid maple shaft.