Dr. Dave's answers to frequently-asked questions (FAQs), mostly from the AZB discussion forum
more information, see Section 4.02 in The
Illustrated Principles of Pool and Billiards,
Disc I of the Video Encyclopedia of Pool Shots, and Disc I of the Video Encyclopedia of Pool Practice
advice and drills
How can I improve my draw stroke?
In general, to get good draw action, you must hit the CB both low and hard. Probably the best advice to accomplish this is to keep your grip relaxed and smoothly accelerate the cue into the ball (i.e., don't jerk or rush the transition from the final backstroke to forward stroke) to create good follow-through. A longer bridge length can help create more power without jerkiness. A closed bridge might help you achieve a lower tip position without adding cue elevation (which can decrease accuracy), especially if you have large hands. More stroke advice can be found here. Also, make sure you have a good tip that is well shaped and textured so it holds chalk. Also, be sure to chalk up before each shot.
If you are having trouble with your draw stroke, make sure you are being careful with the following:
Here are good video demonstrations of draw shot technique advice, physics effects, and game-situation examples:
and here's a good progressive-practice drill to help you improve your draw shot technique, from Disc I of the Video Encyclopedia of Pool Practice (VEPP):
and here's a good video demonstration for power draw advice, from Disc I of The Video Encyclopedia of Pool Shots:
Anytime you practice or do experiments with draw shots, it is important to verify that you are hitting the CB where you think you are. The best way to do this is to use a marked ball (for example, a Jim Rempe CB or an Elephant Practice ball) or a striped ball, and note the location of the chalk mark on the ball after each shot. Just make sure you align the markings on the ball with the line of action of the cue (for example, see the 9-ball stripe in Diagram 1b). People are often surprised by how high the actual tip contact point is on the ball despite how low they might think they are aiming. Sometimes, people just don’t aim low enough on the CB. Sometimes people drop their elbow during the stroke, before tip contact. This brings the tip up, and you get less draw. If you tighten your grip during the stroke, the tip will drop and you might scoop the CB in the air. Always look at the mark on the CB after the shot ... the chalk mark never lies!
It also helps (a lot!) to have a very slick and fast cloth. It is a lot easier to draw the ball on a slick and fast cloth! For more info, see: cloth and cue ball effects.
For more information and advice, see the following series of instructional articles dealing draw shot physics, aiming, applications, technique, and drills:
"Draw Shot Primer - Part I: physics" (BD, January, 2006).
"Draw Shot Primer - Part II: aiming" (BD, February, 2006).
"Draw Shot Primer - Part III: using the trisect system" (BD, March, 2006).
"Draw Shot Primer - Part IV: game examples" (BD, April, 2006).
"Draw Shot Primer - Part V: how to achieve good draw action" (BD, May, 2006).
"Draw Shot Primer - Part VI: draw shot practice drill" (BD, June, 2006).
"Draw Shot Primer - Part VII: tips of english" (BD, July, 2006).
Also see the physics-based draw shot advice resource page.
from Rod (concerning causes for miscuing and "scooping" the ball):
The number one reason. Your grip hand tightens up, in turn so does your arm and shoulder. When that happens it elevates the butt of the cue. Guess what comes next? The tips drops and you hit too far below center. The cue ball goes flying.
If at the same time (which happens a lot) your stroke swerves to either side, then the cue ball squirts off to the side. Nothing worse that that nasty miscue sound.
Tight muscles are shorter and probably slower, relaxed muscles are longer. Stay relaxed, not only will you improve your draw stroke, it will improve every stroke.
Striking the c/b accurately is premium. You need to hit where you addressed the c/b to make the shot come off as planned. If your grip tightens up --- well you know the answer.
You will probably receive all sorts of contradictory advice on this one. The only real requirement is that you hit the ball low. If the object ball is far away, you will also need to hit the ball hard to keep back spin (also known as draw or screw) on the cue ball, as the cloth rubs the spin off. Some things to keep in mind: You must chalk your tip well; most players don't. A shorter bridge (hand to cue ball spacing) will let you hit where you want more accurately. If your elbow is pumping up and down, hitting the intended spot on the cue ball is more of a challenge. Do you jump up at the end of the shot? Do you follow through so the tip ends at least a ball diameter or two beyond the original position of the cue ball, or do you jerk abruptly to a stop at the instant of contact?
from Bob_Jewett (concerning a slightly elevated cue, which causes cue ball hop):
The simple theory is that the cue ball loses a fixed number of RPMs per second on its way to the object ball. If the cue ball is hopping on its way to the object ball, it will lose draw only on the landings, but the simple theory says that the total loss of draw on the way to the object ball will be about the same.
The theory also says that if the cue ball is hopping with draw off an object ball, or maybe hopping from a masse shot, it will travel in straight lines between the landings as seen from above, but the path will take abrupt turns at the times of the landings.
One consequence to practical play of the first paragraph is that to get best draw for a particular stick speed off a distant ball it is sometimes better to cue higher on the cue ball. The closer to center you hit, the faster the cue ball will be going at the start. It is a balance between getting there quickly and not losing as many RPMs and starting with more RPMs and losing more due to the slower cue ball travel.
bridge length effects
What bridge length should I use to get good draw action?
A longer bridge length can help create more power with less jerkiness; but with more length you will get less tip-placement accuracy. Every individual will have an optimal length where these tradeoffs are balanced.
With a shorter bridge, the cue will need to be elevated more to get the low tip position; and with more cue elevation, the effective tip offset from center will be larger for a given tip contact point on the ball (see draw cue elevation effects). This might help some people get more draw because the cue elevation causes them to hit the CB further from center than they would with a level cue. Also, with a shorter bridge, tip placement errors due to grip tightening, elbow drop, or stroke swoop will be reduced (as compared with a longer bridge).
More information about bridge length effects can be found in "Fundamentals - Part IV: bridge length" (December, 2008) and on the bridge length resource page.
See also: draw technique advice and drills section.
The equation for obtaining maximum draw is simple and involves only two things. The cue tip should hit the CB as low as possible and the cue tip should be traveling as fast as possible, all without miscuing. That's all. Bridge length comes into the equation only to the extent as how much it affects tip placement and speed.
A longer bridge might help you obtain greater cue tip velocity on impact (assuming a constant cue acceleration and that stroke length is in proportion to bridge length). However, a shorter bridge might help you in tip placement accuracy such that you more reliably hit the CB as low as possible without miscuing.
Precise cue tip placement is definitely harder to achieve than a high cue tip velocity. So for a beginner, I would recommend a shorter bridge length to obtain greater draw.
from Mike Page:
A consequence of this is for the really best players amongst us, a bridge length close to their own-break shot bridge length might give them maximum draw. This is the bridge length that evidently gives them maximum speed with control. For many of the rest of us, the quality of our tip placement deteriorates more rapidly with bridge length and our optimal bridge length for maximum draw would be shorter. For new players it would be very short, imo.
cloth drag effects
How does the condition of the table cloth and the cue ball affect draw action?
It is easier to get more draw action on a "slick" cloth (i.e., a cloth with low sliding friction), because the cue ball retains more of its bottom spin on the way to the object ball. A "fast" cloth (a cloth with low rolling resistance), will allow the cue ball to roll farther after the draw takes.
If you want to simulate the effects of a "slick" cloth, or if you just want to impress your friends with dramatic draw, try spraying and/or wiping the cue ball with Silicone Spray (spray lubricant available at any hardware store). You will be able to draw like you've never drawn before.
To visualize the "drag" action of the cloth, see:
The thickness of the cloth can also affect how the CB comes off the tip, especially with cue elevation. For more info, see:
For more information on cloth conditions effects, see the cloth effects resource page.
from Patrick Johnson:
It is important to distinguish between rolling friction and sliding friction. The two affect the cue ball in different ways and they are sometimes misunderstood. Sliding friction relates to the force from the cue ball sliding on the cloth. It causes draw to wear off and it allows draw or follow to take effect after the cue ball hits the object ball. Sliding friction can be reduced by getting new (slippery) cloth and by waxing the cue ball. Waxing is an easy experiment to do, and I recommend it to anyone who hasn't tried it yet.
Rolling friction tells you how quickly the cue ball slows down after it is rolling smoothly on the cloth. With low rolling friction, it takes the cue ball a long time to slow down. If you have one available, check out how long the ball rolls on a heated carom table.
All combinations of high and low values of these two kinds of friction are possible. The most extreme case of low/low I've tried was on a waxed linoleum floor. You can do amazing masse shots under such conditions. New carom cloth is the closest on-table example of this combination.
Low rolling resistance and high surface friction occurs sometimes on thin old cloth that's dirty and compressed. An extreme example would be a very hard rubber surface -- the ball would roll for a long time but there is no way you could keep draw on it.
High rolling resistance and high surface friction is what you often get in bars. Dirty, thick cloth, and dirty, rough cue balls.
The most important friction when trying to draw the cue ball is the friction between the cue ball and the cloth on the way to the object ball. That friction can wear off some, most or all of the backspin. You will seem to get a lot more draw by waxing the cue ball so that it loses less draw on the way to the object ball.
Once the cue ball contacts the object ball, the friction will allow the draw to take. Less friction just means that it will take longer for the cue ball to come up to full speed, but the final speed of the cue ball drawing back will be nearly the same regardless of the actual value of the friction ball-to-cloth.
One thing that is most noticeable about a slippery cue ball is the remarkable arc you can get when drawing a cut shot. Because the slippery cloth delays the action, you get a much wider arc.
... something that's a huge factor in many pool halls: the size of the cue ball. The cue ball wears down in play, and if the cue ball is smaller, it is also lighter and much, much easier to draw.
In the case of old cloth, the problem is nearly always that the cloth is sticky, which is to say that there is more ball-cloth friction and the draw wears off faster. Waxing the cue ball in such a situation will often restore new-cloth action for a while until the wax wears off.
from Patrick Johnson:
It's not true that the CB will lose more draw spin as it "peels out" on slipperier cloth - it loses the same amount of spin on any kind of cloth; it just takes a little longer on slippery cloth (see explanation below).
If the CB hits the OB with the same amount of backspin, then the cloth doesn't matter - the cue ball will draw back the same distance on slippery or sticky cloth. But sticky (nappy or dirty) cloth rubs off more of the CB's backspin on its way to the OB and slippery cloth rubs off less. That's why you have to put more backspin on the CB on sticky cloth and why the best cloth for draw is the fastest (slipperiest) cloth.
When the CB hits the OB with the same amount of backspin (or forward spin) it reacts differently on slippery and sticky cloth:
- On slippery cloth it will "peel out" for a longer time and take more time to pick up speed and start rolling naturally, but it will lose spin more slowly.
- On sticky cloth it will "peel out" for a shorter time and take less time to pick up speed and start rolling naturally, but it will lose spin more quickly.
Here's the interesting thing: these two effects balance out so that when the CB has stopped peeling out and starts rolling naturally it will be moving the same speed in both cases and therefore will draw back (or follow forward) the same distance.
P.S. You point out an important distinction that many players don't get: cloth is faster/slower in two separate ways; sliding speed and rolling speed. Fast cloth is usually faster both ways, but not always to the same degree. Some cloth slides really well (so the CB retains lots of draw or follow spin on its way to the OB), but doesn't roll as far as you'd expect, and vice verse. "Slipperiness" (sliding speed) also affects the way balls react off the rails with sidespin.
reply from Jal:
... the cueball will draw back a bit farther on slicker cloth, assuming its rolling resistance is at least the same or less than the stickier cloth's.
cue elevation effects
Does it help to elevate the cue for draw shots?
Cue elevation can help create quick draw with shots at an angle. However, with straight draw shots, there is no physical benefit to elevating the cue. See physics-based draw-shot advice for more info. Not only is physics a problem with elevated-cue draw, reduced accuracy and unintentional swerve can also be factors. Also, with cue elevation, the CB will hop more, which can result in overcutting a shot per jump shot over cut effects.
Now, it is possible that elevating the cue might cause a player to do something different with the amount of tip offset from center or with the stroke. Elevating the cue might help some people hit the CB further from center than they think. A possible reason for this is that for a given tip contact point, the effective tip offset from center is greater with more cue elevation. The following diagram from "Draw Shot Physics - Part IV: cue elevation effects" (BD, July, 2009) illustrates this effect:
Also, when some people elevate the cue, they might accelerate the cue differently, creating more speed at CB impact, which could create more draw.
Now, if a person has large fingers and hands and uses a closed bridge (especially if the closed bridge is high), extra cue elevation might be required to get the tip low enough on the CB, especially if the bridge length is short. Also, if a person tends to drop their elbow during or after the hit on the CB, extra cue elevation might help avoid a collision of the grip hand with a rail or the table surface.
For more information, see cue elevation effects and technique advice.
What does pool physics offer for advice on draw shots?
Here's the list of conclusion, which can be found at the end of TP B.8 (all of the graphs referenced below are clearly labeled in the analysis if you want to check them out):
For more info and illustrations, see "Draw Shot Physics - Part I: basics" (BD, April, 2009) and "Draw Shot Physics - Part II: examples" (BD, May, 2009) and "How High or Low Should You Hit the Cue Ball?" (BD, September, 2011).
With a straight draw shot (with no cut angle), the amount of draw is determined solely by the amount of CB spin at contact with the OB. This is the topic of TP B.8. In TP B.9, I look at both spin and the spin-to-speed ratio. Examples where spin-to-speed ratio is more important than spin are when ...
The graphs mentioned above can be found in TP B.9. For more info and illustrations, see "Draw Shot Physics - Part III: spin ratio" (BD, June, 2009).
TP B.10 - Draw shot cue elevation effects, looks at the effects of cue elevation. Here are the conclusions from the analysis:
Sometimes cue elevation is required to clear over an obstacle ball, or to prevent a double hit when there is a small gap between the CB and OB. And as noted above, with larger cue elevations, better quick draw action can result. However, for maximum draw distance, a level cue (or as close to level as possible) appears to be best. For more info, illustrations, and examples, see "Draw Shot Physics - Part IV: cue elevation effects" (BD, July, 2009).
The math and physics is fairly involved, but here's the basic concept:
With an elevated cue, the CB doesn't lose any speed or spin while it is airborne (between the bounces); however, more speed and spin is lost during the bounces (including the first bounce off the tip, based on HSV B.44) than with a near-level-cue drag shot.
Some people claim they get better draw when they elevate the cue some. Possible explanations for this can be found in the draw-shot cue-elevation effects resource page.
How do you achieve good power draw?
First of all, make sure you follow all of the advice concerning good draw shot technique. Also, many important principles involving power draw can be found in the physics-based advice section. More general advice and video demonstrations can be found in the elbow drop and pendulum stroke section.
Here's a good video demonstration from Disc I of The Video Encyclopedia of Pool Shots:
For more information, see: "Draw Shot Physics - Part I: basics" (BD, April, 2009) and "How High or Low Should You Hit the Cue Ball?" (BD, September, 2011).
Here's a power-draw shot by Mike Massey:
How do you get the cue ball to draw more quickly with a cut shot?
To have the cue ball draw back more quickly at a shorter angle and less tangent-line motion with a cut shot, you want to have as much backspin as possible with as little forward speed as possible. The result is called quick draw. To get the largest effect, you need to elevate the cue (see TP B.9 for more info). Cue elevation also allows one to create less object motion for a given amount of cue ball draw. For examples and more info, see "Draw Shot Physics - Part III: spin ratio" (BD, June, 2009) and "Draw Shot Physics - Part IV: cue elevation effects" (BD, July, 2009). Here are some related videos:
For more info on cue elevation effects, see cue elevation effects.
trisect aiming system
Is there a rule for predicting CB direction for a draw shot similar to the 90-degree rule for a stun shot and the 30-degree rule for a rolling CB shot?
Yes. It is called the trisect system, which applies to a"good action" draw shot for cut angles smaller than about 40 degrees (i.e., ball-hit fraction greater than about 3/8). You can use a modified version of the Dr. Dave peace-sign technique to predict the cue ball direction. Here's a good video demonstration from Disc I of The Video Encyclopedia of Pool Shots:
Here's another video, from Disc II of the Billiard University (BU) Instructional DVD series, that shows how you can use the trisect system effectively when you have ball in hand:
And here's an example from Disc II of How to Aim Pool Shots (HAPS) showing how the trisect system can be used to aim non-ball-in-hand carom shots:
For more information and demonstrations, see:
"HAPS - Part IV: Draw Carom Shot Aiming" (BD, February, 2015).
"Draw Shot Primer - Part III: using the trisect system" (BD, March, 2006)
"Draw Shot Cue Ball Directions" (BD, December, 2011)
where the CB goes for different cases
Here's a convenient 1-page trisect system resource page summarizing the important concepts.
See also: shot speed effects.
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