LD vs regular shafts

BC21

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How about if there was no rotation but 100% tip/ball slippage - like, say, an unchalked tip with grease on it? Would there be squirt then? Or would it be a "carom" like two silicone coated balls colliding off center?

pj
chgo

That would be the same as a miscue, so of course the cb would deflect sideways away from the point of contact.
But not the same as two silicone balls colliding off center. The balls weigh the same and therefore affect each other equally, making it simple to determine directional paths after the collision.

With a cue tip that slips off the side of the cb, a miscue, the exact path of the cb after collision depends on the speed, flexibility, and end mass of the shaft, because the weight of the ball will still deflect/push the shaft offline. The cb path depends on how much and how quickly the shaft moves. Add some chalk and the shaft still gets pushed offline, but the tip grabs and pushes the cb along the stroke path while riding the circumference of the rotating ball for that very brief time period.

I think you are calling squirt something different than cb deflection, and I believe it's the same thing. The cb deflects/squirts out of the cues path, regardless of whether or not the cue tip is covered with silicone or chalk. Naturally it deflects/squirts less with a chalked tip, and even less with LD shafts.
 

Patrick Johnson

Fish of the Day
Silver Member
The cb deflects/squirts out of the cues path, regardless of whether or not the cue tip is covered with silicone or chalk. Naturally it deflects/squirts less with a chalked tip, and even less with LD shafts.
So you're saying when an OB is driven at an angle by a silicone-coated CB it's the same physical dynamic as a CB squirted at an angle by a well chalked tip? Just a difference of degree?

pj
chgo
 

BC21

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So you're saying when an OB is driven at an angle by a silicone-coated CB it's the same physical dynamic as a CB squirted at an angle by a well chalked tip? Just a difference of degree?

pj
chgo

Uhm....no. Now you are messing with me. Lol.

The chalked tip pushes the cb forward while riding along the face of the ball, sending the cb down a path close to the actual stroke path, and at the same time the weight of the ball is forcing the tip away. It's nothing like two balls colliding, with or without silicone It's apples and oranges, no comparison. However, a silicon coated tip on a 6oz cue that has zero shaft flexibility.....well, that would pretty much be the same as a silicone coated ob striking the cb.

Regardless, the op's topic is LD shafts vs regular shafts. So I'm hopping off this tagent, as exciting as it is.
 

dr_dave

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I know Dr Dave will point out that end mass is all that matters
That's not true. Shaft stiffness also directly affects CB defection; although, for typical pool equipment, the direct stiffness effect is much smaller than the "endmass" momentum effect. Shaft stiffness also has an indirect effect on shaft "endmass." That's why I often put "endmass" in quotes. For more information, backed up by lots of experimental and theoretical verification, see:

shaft endmass and stiffness effects

What causes squirt?


but if you could use a robot shooter with no lateral give in the bridge piece or grip arm/piece, and test a cue that has a super light shaft end mass but zero flexibility, then the cb would react to the full weight of the cue stick and deflect out of its way, because the cue stick path would remain fixed.
FYI, I and others have built robots to test shafts for CB deflection, and I and others have performed several experiments testing the effects of shaft "endmass" and stiffness changes with actual pool equipment. As expected, the experimental results support the physics-based facts. For more info, see:

squirt robot test results

Squirt – Part VII: cue test machine results” (BD, February, 2008).

Return of the squirt robot” (BD, August, 2008).


Fortunately we humans have some give in our bridge hand, so there is always some deflected lateral movement of the shaft when the tip strikes the cb. But a more flexible shaft ensures more shaft deflection, which is a good thing, if you like LD shafts.
For typical pool equipment, the lateral motion of the shaft does not reach the bridge hand until the CB is already gone (so the bridge can have no direct effect). For more information and super-slow-motion video proof, see:

squirt bridge length effects

I encourage you and others interested in this thread to read through all of these resources. I and others (Ron Shepard, Bob Jewett, Mike Page, Rod Cross, ...) spent many years thinking about, researching, testing, and analyzing this stuff and the resources document everything we learned. There is always more to be learned, but the I think the basic physics of squirt is already well understood.

Enjoy,
Dave
 
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Patrick Johnson

Fish of the Day
Silver Member
I and others (Ron Shepard, Bob Jewett, Mike Page, Rod Cross, ...) spent many years thinking about, researching, testing, and analyzing this stuff and the resources document everything we learned. There is always more to be learned, but the I think the basic physics of squirt is already well understood.

Enjoy,
Dave
Dave, is there anything on your site that specifically addresses the difference in physical dynamics between ball/ball and tip/ball collisions?

pj
chgo
 

BC21

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That's not true. Shaft stiffness also directly affects CB defection; although, for typical pool equipment, the direct stiffness effect is much smaller than the "endmass" momentum effect. Shaft stiffness also has an indirect effect on shaft "endmass." That's why I often put "endmass" in quotes. For more information, backed up by lots of experimental and theoretical verification, see:

shaft endmass and stiffness effects

What causes squirt?


FYI, I and others have built robots to test shafts for CB deflection, and I and others have performed several experiments testing the effects of shaft "endmass" and stiffness changes with actual pool equipment. As expected, the experimental results support the physics-based facts. For more info, see:

squirt robot test results

Squirt – Part VII: cue test machine results” (BD, February, 2008).

Return of the squirt robot” (BD, August, 2008).


For typical pool equipment, the lateral motion of the shaft does not reach the bridge hand until the CB is already gone (so the bridge can have no direct effect). For more information and super-slow-motion video proof, see:

squirt bridge length effects

I encourage you and others interested in this thread to read through all of these resources. I and others (Ron Shepard, Bob Jewett, Mike Page, Rod Cross, ...) spent many years thinking about, researching, testing, and analyzing this stuff and the resources document everything we learned. There is always more to be learned, but the I think the basic physics of squirt is already well understood.

Enjoy,
Dave

I have read all of this material. Great information, but I was strictly referring to robot testing a shaft with light endmass and ZERO flexibility (which has not been done) simply to show that shaft flexibility is a key factor, along with decreasing shaft endmass, for reducing cb deflection. Maybe it hasn't been done because no such shafts exist, closest being probably an aluminum or graphite shaft. Or maybe because it's common sense and doesn't need to be shown.

Regardless, I understand and respect the depth of information already presented on the matter of squirt/deflection by you and many others, but that work doesn't keep the rest of us from thinking of other experiments and discoveries not already established.
 
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dr_dave

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Dave, is there anything on your site that specifically addresses the difference in physical dynamics between ball/ball and tip/ball collisions?
I analyze each in great detail, but the physics of each is totally different, so I honestly don't think it is helpful to compare them.

With an off-center hit, the cue tip grabs the CB with no slip (except with a miscue) and the cue is long, skinny, and very flexible (not very stiff laterally).

In contrast, when two balls hit, the force is always through their centers (except for a small throwing force), there is very little friction (except when there is cling/skid/kick), and the balls are very stiff (nearly rigid).

Both situations involve impact and momentum transfer, but that's about all that is similar.

Regards,
Dave
 

dr_dave

Instructional Author
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Silver Member
That's not true. Shaft stiffness also directly affects CB defection; although, for typical pool equipment, the direct stiffness effect is much smaller than the "endmass" momentum effect. Shaft stiffness also has an indirect effect on shaft "endmass." That's why I often put "endmass" in quotes. For more information, backed up by lots of experimental and theoretical verification, see:

shaft endmass and stiffness effects

What causes squirt?


FYI, I and others have built robots to test shafts for CB deflection, and I and others have performed several experiments testing the effects of shaft "endmass" and stiffness changes with actual pool equipment. As expected, the experimental results support the physics-based facts. For more info, see:

squirt robot test results

Squirt – Part VII: cue test machine results” (BD, February, 2008).

Return of the squirt robot” (BD, August, 2008).


For typical pool equipment, the lateral motion of the shaft does not reach the bridge hand until the CB is already gone (so the bridge can have no direct effect). For more information and super-slow-motion video proof, see:

squirt bridge length effects

I encourage you and others interested in this thread to read through all of these resources. I and others (Ron Shepard, Bob Jewett, Mike Page, Rod Cross, ...) spent many years thinking about, researching, testing, and analyzing this stuff and the resources document everything we learned. There is always more to be learned, but the I think the basic physics of squirt is already well understood.
I have read all of this material. Great information, but I was strictly referring to robot testing a shaft with light endmass and ZERO flexibility (which has not been done) simply to show that shaft flexibility is a key factor, along with decreasing shaft endmass, for reducing cb deflection. Maybe it hasn't been done because no such shafts exist, closest being probably an aluminum or graphite shaft. Or maybe because it's common sense and doesn't need to be shown.
I don't have much interest in unrealistic and physically impossible situations like this, because a very stiff cue (with very little lateral flexibility) would be useless. The amount of effective endmass and CB deflection would be large, and the direct stiffness effect would be a big factor (unlike with actual pool cues that are very flexible laterally).

FYI, carbon fiber shafts come about as close as physically possible to your "thought experiment." They are strong and stiff enough (longitudinally and laterally) while keeping the end of the shaft as light as possible. The lightness of the shaft end is the dominant factor in reducing CB deflection (squirt). I just did a lateral flex comparison of my carbon fiber Revo to my wood Z-2 (by bending them with a lateral force at the tip), and the Revo is stiffer laterally, but they have very close to the same CB deflection (see NV J.12).

BTW, Mike Page and I have done tests showing that changing shaft stiffness of an actual pool cue (without changing endmass) has very little affect on squirt. See Diagrams 2 and 3, and the surrounding discussion, in “Return of the squirt robot” (BD, August, 2008).

There have also been many experiments showing what happens when the endmass is changed without changing lateral stiffness. For example, see Diagram 1 and the surrounding discussion in the same article.

Also take a look at the following tests and analysis that shows how small the direct stiffness effect is compared to the endmass momentum effect:

TP B.19 – Comparison of cue ball deflection (squirt) “endmass” and stiffness effects

Catch you later,
Dave
 

dr_dave

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I understand and respect the depth of information already presented on the matter of squirt/deflection by you and many others, but that work doesn't keep the rest of us from thinking of other experiments and discoveries not already established.
FYI, you are not the first to think of interesting thought experiments and challenges to the currently-accepted theories for what causes squirt (CB deflection). There have been many threads like this over many years. In fact, most of the questions and answers in the bottom section of the endmass and stiffness effects page have been added as a result of these threads. Please read through the Q&As, especially if you have not seen them in a while (or ever). FYI, I just added an additional Q&A based on the discussion in this thread. If I keep adding answers to all of these sorts of questions to the resource page, maybe there will be less need for these types of threads in the future; although, the threads are still fun and interesting, and I think everybody (me included) learns a little more each time.

Regards,
Dave
 

BC21

https://www.playpoolbetter.com
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Silver Member
FYI, you are not the first to think of interesting thought experiments and challenges to the currently-accepted theories for what causes squirt (CB deflection). There have been many threads like this over many years. In fact, most of the questions and answers in the bottom section of the endmass and stiffness effects page have been added as a result of these threads. Please read through the Q&As, especially if you have not seen them in a while (or ever). FYI, I just added an additional Q&A based on the discussion in this thread. If I keep adding answers to all of these sorts of questions to the resource page, maybe there will be less need for these types of threads in the future; although, the threads are still fun and interesting, and I think everybody (me included) learns a little more each time.

Regards,
Dave

I certainly don't believe that I am the first to think of new experiments or ideas in pool, but I also know I'm not the only one or the last one or the smartest one. A great teacher once told me to question everything.
That's how we learn new things, undiscovered or unthought of things. If something doesn't seem logical, question it, regardless of what authority is presenting the material or information.

Like you, I thought with Mike Page's "Beaver Cue" experiment the 90° and 270° orientations would produce the highest cb squirt. Now I can't help but think something else was going on with that experiment, or in the recording of the shaft orientations, that ended up throwing logic out the window. It's like the 90 and 270 orientations were recorded as 0 and 180. Lol.

Anyway, the info is very well documented, respected, and appreciated.
 

hang-the-9

AzB Silver Member
Silver Member
I certainly don't believe that I am the first to think of new experiments or ideas in pool, but I also know I'm not the only one or the last one or the smartest one. A great teacher once told me to question everything.

Careful with that "question everything" part, that is a dangerous area to use as a general rule and is how we get flat earthers and most of the conspiracy theory nuts (no moon landing, 911, etc..).
 

dr_dave

Instructional Author
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Silver Member
I certainly don't believe that I am the first to think of new experiments or ideas in pool, but I also know I'm not the only one or the last one or the smartest one. A great teacher once told me to question everything.
That's how we learn new things, undiscovered or unthought of things. If something doesn't seem logical, question it, regardless of what authority is presenting the material or information.
Agreed. Although, proposed answers to questions that go against currently-accepted (and well tested) theories should also be tested and analyzed carefully before trusting them as fact. This is especially important in today's world of Internet-fueled "alternative facts." :frown:

Anyway, the info is very well documented, respected, and appreciated.
You're welcome ... and thank you. I aim to swerve. :grin-square:

Best regards,
Dave
 

BC21

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Careful with that "question everything" part, that is a dangerous area to use as a general rule and is how we get flat earthers and most of the conspiracy theory nuts (no moon landing, 911, etc..).

Lol...well, I don't ignore common sense or logic.
 

JessEm

AzB Goldmember
Silver Member
Lol...well, I don't ignore common sense or logic.

Which is necessary in order to believe JFK and 911 were not conspiracies.

A poll was done on Americans regarding 911 by one of the big outfits (don't remember where I seen it but it was within the last year). It showed most American's believe 911 was a conspiracy to one extent or another. The percentage was pretty high.
 

BC21

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Which is necessary in order to believe JFK and 911 were not conspiracies.

A poll was done on Americans regarding 911 by one of the big outfits (don't remember where I seen it but it was within the last year). It showed most American's believe 911 was a conspiracy to one extent or another. The percentage was pretty high.

That just tells me that most of those who participated in the poll were influenced by something other than their own common sense. The JFK shooting, however, does contain some very odd facts that don't exactly add up, and that doesn't mean it's a conspiracy, just that there are things that don't make sense. The same can be said of many events throughout history. Like history itself, some things are true, some things are partly true, and some things are completely fabricated. The only 100% true thing is that anything considered "official" (as far as history goes), is whatever the leaders of the time consider "official".

Now I must get back to playing pool before darkness falls and my hunt for Bigfoot begins.🤪 lol
 

JessEm

AzB Goldmember
Silver Member
That just tells me that most of those who participated in the poll were influenced by something other than their own common sense. The JFK shooting, however, does contain some very odd facts that don't exactly add up, and that doesn't mean it's a conspiracy, just that there are things that don't make sense. The same can be said of many events throughout history. Like history itself, some things are true, some things are partly true, and some things are completely fabricated. The only 100% true thing is that anything considered "official" (as far as history goes), is whatever the leaders of the time consider "official".

Now I must get back to playing pool before darkness falls and my hunt for Bigfoot begins.🤪 lol

Neither add up but 911 is even crazier... For me, the single strangest thing is the news reporting the collapse of building 3 well before it collapsed... Then there's the way it went down, by all demolition experts standards, like a perfectly executed demolition... There's a large contingent of Scientists and Structural Engineers who've studied those buildings and are adamant they could not have collapsed as reported... Wasn't there some high-ranking official caught smuggling out documents in his shorts before the "911 Commission"? lol
 

henrylr

AzB Silver Member
Silver Member
tyrin to understand LD shafts

I'v read a few discriptions of how LD shafts work, but I have a question on how they work that may help me understand. Is the lenght of the tip of the shaft, four or five inches more fexible, such that the tip deflects, on contact with the cue ball, thus causing less deflection of the cue ball?

Thanks for any answeres
 

Patrick Johnson

Fish of the Day
Silver Member
Is the lenght of the tip of the shaft, four or five inches more fexible, such that the tip deflects, on contact with the cue ball, thus causing less deflection of the cue ball?
No, shaft flexibility has little to do with cue ball deflection (squirt). Squirt is caused by the rotating cue ball pushing sideways against the mass (weight) of the tip and pushing itself sideways in the process. Less "end mass" in the shaft means less weight to push aside, so the effect is like a more flexible shaft but for a different reason. That's why lots of low squirt shafts are hollow near the tip but many are stiffer than common high squirt shafts (for instance, the new carbon fiber shafts).

pj
chgo
 

dr_dave

Instructional Author
Gold Member
Silver Member
I'v read a few discriptions of how LD shafts work, but I have a question on how they work that may help me understand. Is the lenght of the tip of the shaft, four or five inches more fexible, such that the tip deflects, on contact with the cue ball, thus causing less deflection of the cue ball?

Thanks for any answers
If you want thorough and complete answer, see:

LD shafts

what causes squirt?

Enjoy,
Dave
 

JohnnyOzone

AzB Silver Member
Silver Member
Which is necessary in order to believe JFK and 911 were not conspiracies.

A poll was done on Americans regarding 911 by one of the big outfits (don't remember where I seen it but it was within the last year). It showed most American's believe 911 was a conspiracy to one extent or another. The percentage was pretty high.

You know, most times it's better to remain silent and perhaps be thought a fool, rather than to open your mouth and remove all doubt.
 
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