A Closer look at L.D. Shafts

[Barioni Cues]

Various speed in robot tests

I have read some of the posts here and I want to clear something up.
We have had the robot for nearly a year. Before the robot we had other testing jigs but I must admit the other testing equipment was no where as sophisticated or as accurate as this machine. The part I want to clear up is my robotic machine which I would like to refer as a Pool Cue Dyno has the ability to produce various speeds from super soft roll to break speeds in seconds. Very easy to adjust. We have tested all these variables at various speeds. The higher the speed the more cue ball deflection. So most of our testing now in done at the speed of what 80% of your shots should be which is hard enough to take out the table roll but soft enough to make the pocket play as big as possible. To hard and you rattle balls and make the pocket play tight. To soft you pick up the table roll if it has any. And as we all know most of them do.

 

[woody_968]

So if a smaller tip contacts the cueball at he exact same place as a larger tip the larger tip would actually put more spin on the cueball?

I have had many debates with a friend of mine on this subject. He has always said a small tip spins the ball more. I have always said your more accurate with where you are trying to contact the cueball with a smaller tip, but thought the actual contact patches would be close to the same size if using the same shape tip so there shouldnt be much difference in produced spin.

Comparing the spin produced with different tip sizes is one of the portions of your study that interest me the most.

Thanks.

 

[Barioni Cues]

My opinion is you should write a report for each test or series of tests that you did. Use the scientific method to format you report. Describe your hypothesis, experiment, test data, and conclusion. If you spent all this time making test equipment, and performing the actual tests, you need to close the loop and make coherent reports on your findings. Paragraphs after paragraphs in this thread will not do justice to the trouble you went through.

Its also important from a peer review standpoint, that we know what your thought process was. For example, in your reply above comparing small to large diameter tips, you say when aimed the same way, they hit different parts of the cue ball. What does this mean, specifically? (that is a rhetorical question). I personally find fault with a test method that keeps the centerline of the cue in the same spot, as opposed to the contact point. Maybe I'm wrong, maybe I'm right... that is not the point. The point again is for this to be "scientific" you have to be very specific in how you report your experiments. Again, I urge you to consult your physicist for the "scientific method".

I don't mean to discourage you in any way, I hope I'm not coming across that way. Its just its obvious you put in a ton of effort. You have to finish strong now.

Well I truly value your input. But what your asking will take a ton of my time that I don't have. I will not get paid for this time and I'm loosing money in the shop. Further more I have customers with cues on order that want to see progress on their cues. I can't spend all this time typing and inputting these reports and make cues too. You have to remember I suck at typing. So unfortunately I will be forced to give up on this thread or try to find some volunteers or free help with this thread.

 

[Patrick Johnson]

So if a smaller tip contacts the cueball at he exact same place as a larger tip the larger tip would actually put more spin on the cueball?

I have had many debates with a friend of mine on this subject. He has always said a small tip spins the ball more. I have always said your more accurate with where you are trying to contact the cueball with a smaller tip, but thought the actual contact patches would be close to the same size if using the same shape tip so there shouldnt be much difference in produced spin.

Comparing the spin produced with different tip sizes is one of the portions of your study that interest me the most.

Thanks.

The contact patch from different size tips are about the same. Contact patches made by tips of different hardness would be somewhat different, but there wouldn't be a practical difference in the amount of friction or spin. In fact, I can't think of a shaft or tip characteristic that makes a difference in the amount of spin produced by hitting the same CB contact point.

pj
chgo

 

[Patrick Johnson]

The higher the speed the more cue ball deflection.

Other tests have shown that when swerve is eliminated squirt is unchanged by speed differences.

pj
chgo

 

[D4nutz]

Sad and a lil' bit dissappoited

Hi there,

I have read every comment on this thread and i have to say I am bummed out because of your last comment. I am so interested on the results you have produced with that Dyno that I am willing to be one of the volunteers that could keep this thread alive and bring light into the minds of some pool players (mine included).

Please PM me if I could be of any assistance.

Respectfully,
Dan

Well I truly value your input. But what your asking will take a ton of my time that I don't have. I will not get paid for this time and I'm loosing money in the shop. Further more I have customers with cues on order that want to see progress on their cues. I can't spend all this time typing and inputting these reports and make cues too. You have to remember I suck at typing. So unfortunately I will be forced to give up on this thread or try to find some volunteers or free help with this thread.

 

[Barioni Cues]

So if a smaller tip contacts the cueball at he exact same place as a larger tip the larger tip would actually put more spin on the cueball?

I have had many debates with a friend of mine on this subject. He has always said a small tip spins the ball more. I have always said your more accurate with where you are trying to contact the cueball with a smaller tip, but thought the actual contact patches would be close to the same size if using the same shape tip so there shouldnt be much difference in produced spin.

Comparing the spin produced with different tip sizes is one of the portions of your study that interest me the most.

Thanks.

There are a lot of other variables that are missing here. And there important because it can go both ways kind of. You are not more accurate with where you are trying to contact the cue ball with the small tip in the since that the smaller tip will hit more to the out side of center. Hitting farther out side of center will put more spin. A big factor here is whether your using a soft tip or hard tip and the shape of the tip. The bigger tip is covering more of center ball so it is not putting as much spin but it has a bigger contact area and more grip. That is why most trick shot cues and masse cues are 14mm. Bigger tires in drag racing have more contact with the asphalt and provide more traction. The bigger tip provides more grip or in drag racing terms "traction". If your shaft is stock and not been hot rodded so to speak, the bigger tip will cause more squirt. With more power being converted to squirt you have less power being converted to spin. Wow this is taking forever to type. The robot test shows the smaller tip deflects less and puts more spin than a bigger tip if both shafts are stock meaning nothing has been done to enhance the performance. I can make a 14mm deflect less and put more spin than a stock 12mm. There are a lot of variables involved in this scenario that can change this outcome. In the other case unintentional english when trying to hit center ball has to be considered. If your stroke is off with the big tip, since it covers more of center ball the cue ball has less squirt making it more accurate. If your stroke is is off with a small tip and you are trying to hit center ball, you are unintentionally going to put english on the ball causing squirt therefore making it less accurate. There are a lot of thing to be considered here.

 

[woody_968]

Thank you for all the time you have put into this. If there is anything I can do to help you get this information out please feel free to contact me. I would be more than happy to donate my time to help.

 

[Barioni Cues]

The contact patch from different size tips are about the same. Contact patches made by tips of different hardness would be somewhat different, but there wouldn't be a practical difference in the amount of friction or spin. In fact, I can't think of a shaft or tip characteristic that makes a difference in the amount of spin produced by hitting the same CB contact point.

pj
chgo

a more flexible shaft bends out of the way allowing the cue ball to go straighter in the forward position. A stiffer shaft does not bend out of the way allowing the sideways force to squirt the ball. This is one shaft characteristic example that makes a huge difference. The less the cue ball squirts the power being used to spin the ball. In the case of tip shape, in order for a nickle shaped tip to hit the same contact point as a dime, the nickle shaped tip has to go farther off center. A dime shape is relieved more so it doesn't make contact with the ball. This is hard to explain and diagrams are needed to explain this. This is a lot easier to explain in person where I can show it actually happening. Maybe some of this will have to be made in a video where you can see it happening and with detailed diagrams explaining what is going on. I can already see how time consuming this can be.

 

[TATE]

What is the best taper for low squirt?

 

[ENGLISH!]

a more flexible shaft bends out of the way allowing the cue ball to go straighter in the forward position. A stiffer shaft does not bend out of the way allowing the sideways force to squirt the ball. This is one shaft characteristic example that makes a huge difference. The less the cue ball squirts the power being used to spin the ball. In the case of tip shape, in order for a nickle shaped tip to hit the same contact point as a dime, the nickle shaped tip has to go farther off center. A dime shape is relieved more so it doesn't make contact with the ball. This is hard to explain and diagrams are needed to explain this. This is a lot easier to explain in person where I can show it actually happening. Maybe some of this will have to be made in a video where you can see it happening and with detailed diagrams explaining what is going on. I can already see how time consuming this can be.

The highlighted 'sentence' is confusing to me. Can you please clarify your meaning? I appreciate your time & effort considering that you like I am not a 'typist'.

Best Regards & Merry Christmas,

 

[Barioni Cues]

Other tests have shown that when swerve is eliminated squirt is unchanged by speed differences.

pj
chgo

Look at it this way. If a train was going ten miles an hour and hit a guy on a motorcycle it would knock the motorcycle over and probably propel it a few feet. On the other hand if the train was going 80 miles an hour it would propel that motorcycle a long way. When the shaft is coming at the cue ball at a higher rate of speed it knocks the cue ball harder and further off line. The same example could be made using two balls. A cue ball and an object ball. When a cue ball is shot soft doing a cut shot, the friction carries the object ball off line. This is sometimes referred to as drag. A harder shot has less drag and therefore the object ball stays truer to the tangent line. The tip is round just like the cue ball in this example. The better the chalk, the more friction. The more friction the more the cue ball at a slower speed wants to deviate off the tangent line. The harder or faster the speed the more the cue ball wants to go down the tangent line. This tangent line is the angle the contact points produce between the tip and cue ball.

 

[Barioni Cues]

What is the best taper for low squirt?

Flexible. The more flexible to a point, the less squirt. Once you reduce the max squirt by making a shaft flexible then you start to loose power in the cue.

 

[AtLarge]

Perhaps you could start with a summary list of your research results. Readers could comment on or question particular results, and you could supply the supporting detail as needed.

As an example, take a look at Dr. Dave's list of the important squirt, swerve, and throw effects, given here below the videos: http://billiards.colostate.edu/threads/aiming.html#English_effects

 

[Barioni Cues]

The highlighted 'sentence' is confusing to me. Can you please clarify your meaning? I appreciate your time & effort considering that you like I am not a 'typist'.

Best Regards & Merry Christmas,

oops! I left some words out here. Sorry.
The less the cue ball squirts the more power being used to spin the ball. This is what I meant to say. The force or power is absorbed three ways. So much goes to squirt, so much goes to the cue ball going straight, and so much goes to spin. The less force going to squirt ups the percentage of force going to spin and propelling the cue ball straight. My dyno shows this. The less squirt the more the cue ball spins. This is how we know this. I put the striking pad with the NCR paper on the side rail. So the cue ball was fired to the foot rail and the spin made it hit the striking board on the side rail. The more spin the closer the dot was to the foot rail. The least squirting shaft made the closest dot to the foot rail indicating more spin. The cue ball was hitting the same spot on the foot rail for both shafts.

 

[ENGLISH!]

Thanks,

I thought that was what you meant but I would rather have you state it. I will be one that is very interested in seeing your full results.

Thanks again,

 

[ignomirello]

very interesting

Flexible. The more flexible to a point, the less squirt. Once you reduce the max squirt by making a shaft flexible then you start to loose power in the cue.

Wow very interesting I thank you for your time

 

[TATE]

Flexible. The more flexible to a point, the less squirt. Once you reduce the max squirt by making a shaft flexible then you start to loose power in the cue.

So I assume a shaft that measures 12mm all the way for 16" from the tip is pretty low squirt - exactly the kind of shaft I hate to play with!

 

[Patrick Johnson]

a more flexible shaft bends out of the way allowing the cue ball to go straighter in the forward position. A stiffer shaft does not bend out of the way allowing the sideways force to squirt the ball. This is one shaft characteristic example that makes a huge difference.

Tests have shown that (at least within normal ranges) shaft stiffness doesn't affect squirt to a significant degree. For instance, I have a very stiff shaft that produces less squirt than any commercially available shaft because it has very low end mass. On the other hand, some very whippy shafts produce a lot of squirt because of very high end mass.

The less the cue ball squirts the [more] power [is] being used to spin the ball.

For the same contact point on the CB, the amount of squirt shouldn't affect the amount of spin to a significant degree. I've tested this myself, and it also stands to reason (given that both shafts must produce the same force vector through the cue ball in order for it to go in the same direction).

The least squirting shaft made the closest dot to the foot rail [on the side rail] indicating more spin. The cue ball was hitting the same spot on the foot rail for both shafts.

If the CB contact point is the same this shouldn't be true. To hit the same spot on the foot rail you'd have to change the setup - are you sure you hit exactly the same CB contact point (measured perpendicular to the CB's path)?

In the case of tip shape, in order for a nickle shaped tip to hit the same contact point as a dime, the nickle shaped tip has to go farther off center.

The nickel tip's center is farther from the CB's center, but since (as you say) the contact point is the same there should be no difference in the amount of spin or squirt.

This is hard to explain and diagrams are needed to explain this. This is a lot easier to explain in person where I can show it actually happening. Maybe some of this will have to be made in a video where you can see it happening and with detailed diagrams explaining what is going on. I can already see how time consuming this can be.

Yes, these are difficult things to visualize and understand, and the facts often don't agree with what our intuition tells us.

I appreciate the time and effort you're putting into this and hope you'll take my comments in the constructive way I intend them.

pj
chgo

 

[CJ Wiley]

This is accurate from my experience and why a consistent shot speed is so important

Look at it this way. If a train was going ten miles an hour and hit a guy on a motorcycle it would knock the motorcycle over and probably propel it a few feet. On the other hand if the train was going 80 miles an hour it would propel that motorcycle a long way. When the shaft is coming at the cue ball at a higher rate of speed it knocks the cue ball harder and further off line. The same example could be made using two balls. A cue ball and an object ball. When a cue ball is shot soft doing a cut shot, the friction carries the object ball off line. This is sometimes referred to as drag. A harder shot has less drag and therefore the object ball stays truer to the tangent line. The tip is round just like the cue ball in this example. The better the chalk, the more friction. The more friction the more the cue ball at a slower speed wants to deviate off the tangent line. The harder or faster the speed the more the cue ball wants to go down the tangent line. This tangent line is the angle the contact points produce between the tip and cue ball.

This is accurate from my experience and why a consistent shot speed is so important. If you favor one side of the cue ball every time except on straight in shots you increase your ability to judge and calculate what the cue ball is doing every time.

Favoring the inside part of the cue ball is even more essential to reducing unnecessary calculations. Less calculations also reduce the "human error" part of the game and allow you to fall into more of a "zone" which is also essential to maximize your abilities.