Tip position and cue ball spin at CB/OB impact are two different things!

Tin Man

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This sounds obvious, right? But I'm amazed at how often even strong players don't have this concept clear in their mind and how that translates into mistakes.

During this post I'm going to focus on the vertical axis, from draw to topspin. And to keep it simple let's say there are five levels of spin:

1) Draw. Full zippy backspin.
2) Punch draw. My own word for when the cue ball has just a small amount of backspin and dribbles slowly back a little bit.
3) Slide. Stop/stun type of hit, the cue ball is sliding at impact.
4) Punch follow. My own word for when the cue ball is turning forward but not fully rolling, a 'stun run through' type of hit.
5) Follow. Natural roll.

Due to friction on the table the most energy efficient way for the cue ball to move is to roll. This means that as time passes any trace of backspin wears off and it will develop into a naturally rolling ball. Even if you cue with maximum draw it will still turn into a roll shot given enough time, this is the 'drag draw'. Time across the felt equates to descending down these levels towards roll. It turns out that Time = Distance x Speed, so distance and soft speeds equate to a lot of time across the table which is why it is difficult to draw the ball when shooting from distance or at soft speeds.

So what are the common mistakes I see people make?

1. Cueing high unnecessarily. (Diagram 1). When shooting a medium speed follow shot from distance they cue way too high. Why? The table will develop the roll on the cue ball anyway, there is no reason to make the shot more difficult by shooting extremely high. Just cue half a tip above center and let the cue ball develop roll on it's own. A common mistake is to think that cueing very high gives it 'overspin', but in reality the highest you can strike the cue ball will just have it rolling naturally off the tip. Overspin can only be achieved when the cue ball strikes an object ball. Similarly 'force follow' is a weird term. Follow is just roll, so 'force follow' is just a fast roll. When I set up shots with follow for my students they'll ask me "How high are you hitting that?" and I respond "I consider the distance and speed, then I cue just high enough to ensure it is fully rolling when it reaches the object ball. Letting the table develop roll is very important as you add sidespin, because if you're cueing high you can't get as far to the side, so you are limiting your tools by habitually going to the top of the ball without need.

2. Not cueing high enough when they are close to the object ball. (Diagram 2). This is the opposite of the last example. Players shoot most follow shots softly or from a few feet away and get some help from the table to develop a full roll. Suddenly they need to shoot a follow shot from close distance with medium speed and they end up with a stun run through. Ironically they think because they didn't follow far enough they needed more speed, whereas that would actually make the cue ball follow less (it would pick up even less roll en route to the object ball). I say it this way: "If you want the cue ball to follow someone has to make it roll, you or the table. If you're shooting far/soft you can cue center, if you're shooting firm/close you better cue high because you're not getting any help!"

3. Shooting all stun shots half a tip low with firm speed. (Diagram 3). I've seen 650 players do this. In their mind a stun shot is a half tip low with firm speed. In reality a stun simply means that the cue ball is sliding at impact. The same way you can shoot stop shots with a variety of speeds and tip positions you can do the same with stun shots. The lower you start your tip the softer you can cue and still retain a sliding ball. The soft stun shot is one of the most important tools in pool and is surprisingly underdeveloped by almost all players. Often I see people shoot stun shots too hard to keep their slide and overrun their position. Cue low and learn how to make the cue ball crawl, not race, down the tangent line.


This may all seem obvious but it can't be because I work with players between 550-650 week after week and they all struggle in one or more of these areas. What prompted this post is this thread: https://forums.azbilliards.com/threads/object-ball-throw.536131/ Let me ask you a question: What is the difference between #2 (medium hit rolling cue ball) and #3 (medium hit cue ball with high spin)? High spin is just roll, so if the speed is the same then they are the same shot. Where your tip strikes the cue ball doesn't matter, the only question is what is the speed and is the cue ball fully rolling at contact.


In summary, just be aware that there is a difference between where your tip strikes the cue ball and what the cue ball is doing at CB/OB impact. Having a better model of how the balls work is critical to mastering this game.



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buckshotshoey

AzB Silver Member
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On some shots, I dont want the cue ball to slide. So I apply what I call "rolling" english. It's a judgment how high to hit the cue ball in relation to the speed you're going to hit it. I want the cue ball to start rolling@tip contact but not to the point of putting follow on it.

Good write up.
 

Black-Balled

AzB Silver Member
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Some interesting points there, but you have failed to account for margin of error.

Yes, one can do that drag draw shot to make cue ball roll forward just a little bit, or one can hit it centre ball much firmer and get the same result.

Drag draw has many subtleties, which combine to leave a lot of potential break-down points.
 

Tin Man

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On some shots, I dont want the cue ball to slide. So I apply what I call "rolling" english. It's a judgment how high to hit the cue ball in relation to the speed you're going to hit it. I want the cue ball to start rolling@tip contact but not to the point of putting follow on it.

Good write up.

Thank you buckshot.

One point though is there isn't a difference between a rolling cue ball and a following cue ball. A follow shot is just what happens when a rolling cue ball hits the object ball.
 

Tin Man

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Some interesting points there, but you have failed to account for margin of error.

Yes, one can do that drag draw shot to make cue ball roll forward just a little bit, or one can hit it centre ball much firmer and get the same result.

Drag draw has many subtleties, which combine to leave a lot of potential break-down points.

Hey black balled. Yes, the drag-draw is tricky. I used to play it a lot as a kid, now I use more soft stuns and stun run throughs. The drag draw can go wrong if you cue at all off center by mistake in which case it will swerve. Sliding balls are much more accurate.

But none of this changes the point of how the balls work. What the right shots are is one thing, how the balls work is how they work. Also, none of my shots outlined used a drag-draw, that was just an example of how backspin wears off. I agree it isn't my favorite tool for most situations.
 

vinay

Registered
Overspin can only be achieved when the cue ball strikes an object ball. Similarly 'force follow' is a weird term. Follow is just roll, so 'force follow' is just a fast roll.
I'm not sure I "follow". My understanding is that if you hit a firm stroke sufficiently above-center you'd get it rolling forward faster than a natural roll. That extra spin will wear off an speed the cue ball up the analogous to how backspin wears off and slows the cue ball down until it starts rolling naturally. But if cue ball strikes and object ball before that happens, it will roll further forward than it would with a natural roll.

I'd agree it's hard to execute and probably of limited utility, though.
 

Tin Man

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I'm not sure I "follow". My understanding is that if you hit a firm stroke sufficiently above-center you'd get it rolling forward faster than a natural roll. That extra spin will wear off an speed the cue ball up the analogous to how backspin wears off and slows the cue ball down until it starts rolling naturally. But if cue ball strikes and object ball before that happens, it will roll further forward than it would with a natural roll.

I'd agree it's hard to execute and probably of limited utility, though.
I'm glad I started this thread then!

Check out this 6 minute video. Watch to the end and you'll have a new understanding!

 

Tin Man

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Here is what Bob Jewett said about overspin off the tip (found in the comment section):

"Some people think it is necessary to have overspin to get good action on the cue ball. In fact smooth rolling is about the best you can get. Other (more expensive) experiments have shown very slight overspin which will quickly dissipate. If you have overspin when the cue ball hits the object ball, you can follow through at a straighter angle. It's real hard to get such overspin and it doesn't stay on the cue ball for long."


It sounds like it takes a perfect tip strike and any overspin wears off almost instantly. I've never seen this used in a game. Since Mike Page couldn't demonstrate it in his attempts I have moved it to the 'totally impractical' category of shots. Using a hard, miscue limit hit to get a slight trace of overspin that wears off in an inch might be possible, but for all practical purposes the best you can achieve is roll.
 

buckshotshoey

AzB Silver Member
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Thank you buckshot.

One point though is there isn't a difference between a rolling cue ball and a following cue ball. A follow shot is just what happens when a rolling cue ball hits the object ball.
Correct. That was just sort of how I tried to explain it. Sometimes I don't want the cue ball to slide at all. So I try to start it off rolling at tip contact with 1/2 tip high from Center. But, the harder you hit it, the higher you have to apply the cue tip to keep it from sliding
 

vinay

Registered
I'm glad I started this thread then!

Check out this 6 minute video. Watch to the end and you'll have a new understanding!
That's an interesting experimental setup, but the scientist/engineer in me has to point out the flaw in your design. The cue ball will be airborne after a high speed above-center hit, so it wouldn't actually detect overspin. You can actually see the hop if you advance the video frame-by frame.

Let me reiterate though that I don't disagree with your overall point that it's hard to execute and of very limited use even if you could. The only reason you'd want to use force follow is to make the cue ball go straighter i.e. closer to the original path than a rolling cue ball... but the fact that you have to hit it at a high speed defeats that because the cue ball will persist on the tangent line longer before the follow takes effect.
 

Tin Man

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That's an interesting experimental setup, but the scientist/engineer in me has to point out the flaw in your design. The cue ball will be airborne after a high speed above-center hit, so it wouldn't actually detect overspin. You can actually see the hop if you advance the video frame-by frame.

Let me reiterate though that I don't disagree with your overall point that it's hard to execute and of very limited use even if you could. The only reason you'd want to use force follow is to make the cue ball go straighter i.e. closer to the original path than a rolling cue ball... but the fact that you have to hit it at a high speed defeats that because the cue ball will persist on the tangent line longer before the follow takes effect.

Agreed.

There is theory and there is practice. I am more of a practice guy. There are many people more knowledgeable about the physics of the game than I am. I just focus on running balls. From what I've seen the concept of overspin prior to object ball contact has caused damage to a lot of pool games. If you really want to go through the tangent line you can elevate a little and try to skip on through with a half jump shot. That is much more practical.

Thanks for the friendly and useful conversation!
 

FeelDaShot

AzB Silver Member
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Agreed.

There is theory and there is practice. I am more of a practice guy. There are many people more knowledgeable about the physics of the game than I am. I just focus on running balls. From what I've seen the concept of overspin prior to object ball contact has caused damage to a lot of pool games. If you really want to go through the tangent line you can elevate a little and try to skip on through with a half jump shot. That is much more practical.

Thanks for the friendly and useful conversation!
Great post Tin Man. However, I don't think overspin is as hard to achieve as you and Mike Page are saying. I've seen plenty of extreme follow shots where the cue ball has so much spin that it severely bends forward off the object ball to miss a scratch. I don't think this can be achieved without overspin. Some bend is normal with a rolling cue ball but the big bends are definitely from the overspin.

Just my opinion, I'm not a physics expert either.
 

Tin Man

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Great post Tin Man. However, I don't think overspin is as hard to achieve as you and Mike Page are saying. I've seen plenty of extreme follow shots where the cue ball has so much spin that it severely bends forward off the object ball to miss a scratch. I don't think this can be achieved without overspin. Some bend is normal with a rolling cue ball but the big bends are definitely from the overspin.

Just my opinion, I'm not a physics expert either.

When I say "Overspin" I am meaning that the cue ball is spinning forward with more than a natural roll.

Once a cue ball hits the object ball with a thick hit it will absolutely overspin. That is because the object ball takes some of the cue ball speed but none of the spin, so the spin to speed ratio can be much greater than 1:1 (with a 3/4 ball hit you are left with 1/4 of the cue ball speed, so I consider that a 4:1 spin to speed ratio in my caveman mind, but certainly more forward spin than a natural roll or more than you can put on off the cue tip). My point is that off the tip the ratio of spin:speed will max out at 1:1. If someone wants to argue that it can be 1.05:1 for an inch they can feel free to quibble.

This is an example of overspin after object ball contact:
Importantly you can shoot this shot with a 1/2 tip above center if you are table length and shoot medium firm. The cue ball will develop natural roll and this turns into overspin after it contacts the object ball with a thick hit. There is no need for extreme high or extreme power on this shot (unless you are very close to it in which case you need to hit high). The guy in the video says "It takes a very, very strong topspin to do this" but that is due to his lack of understanding, the same I hear echoed from my students and in this post. I have to take a deep breathe and remind myself this is my competition.

The bends you described seeing in your post where the cue ball arcs after object ball contact are from a naturally rolling ball sliding along the tangent line and then bending forward. The cue ball is only rolling naturally up until object ball contact.

Many people hurt their game by trying to make the cue ball overspin off the tip. They end up hitting too hard (which has the opposite effect of going through the tangent line more quickly as pointed out by vinay mentioned) or they miscue or miss. And none of it does any good. Just understand that you're capped out by a natural roll, there is nothing more until after object ball contact, and learn to understand how the distance and speed will do much of your work for you.
 

dendweller

AzB Gold Member
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Agreed.

There is theory and there is practice. I am more of a practice guy. There are many people more knowledgeable about the physics of the game than I am. I just focus on running balls. From what I've seen the concept of overspin prior to object ball contact has caused damage to a lot of pool games. If you really want to go through the tangent line you can elevate a little and try to skip on through with a half jump shot. That is much more practical.

Thanks for the friendly and useful conversation!
That is news to me. My original question may have been a little misguided but I'm glad I asked it.
 

Tin Man

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That is news to me. My original question may have been a little misguided but I'm glad I asked it.
thank you dendweller. I see you are recently joined. I mean no disrespect to your post. I think learning how to maximize and minimize throw is a great conversation and am glad to see you studying and growing as a player. I appreciate you taking my post as a contribution and not a criticism. This is truly how I mean it.
 

td873

C is for Cookie
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You can get overspin at tip contact. About this much [______] lol

I'm sure Dr. Dave will chime in, but here's an old high speed video of his.
 

Bavafongoul

AzB Silver Member
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You lost credibility with me when you over diagnosed and then tried translating what happens with a draw stroke by correlating cue ball movement with time. You started with stating the obvious by writing about friction on the cloth.

Then you continue saying the most efficient way for the cue ball to move is roll. Gosh, I don’t know what to observe
about that other the only way I can imagine any cue ball moving is by lifting it, pushing, dragging and/or rolling it.

So when your wrote the most energy efficient way for the cue ball to move is roll, it made me wonder what else way is there in the games of pool or billiards? You stated that backspin wears off because of time passage but it’s really from frictional energy loss from rolling on the cloth. I suppose one could calculate the length of time it takes the cue ball to travel but it’s really not about the amount of time a cue ball rolls. It’s the velocity of the roll derived determined by the components in a cue stroke consisting of speed, shaft extension and tip position when striking the cue ball, not its length of time rolling.

Time could be a measurement of ball movement. Perhaps some day baseball announcers will broadcast games telling
listeners the pitcher just threw a .97 second fastball versus his last pitch that was a 1.89 seconds change up. Golf announcers already tell us about swing velocity, launch angle, spin rate & fairway roll. I suppose it’s only a question of when hang time is added. Time doesn’t have much significance in pool other than matches take way too long and that a shot clock sure would help. You possess a lot of pool knowledge but your translation came across as spurious, IMO.
 
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