Rules of Thumb in Pool

[randallt6]

Good work, and great thread. FYI, several other useful rules of thumb can be found here:

Top 100 Pool and Billiards "Secrets" and "Gems"​

The following are good additions to your list:

• The trisect system predicts the angle the CB direction changes for a good-action draw shot is 3-times the cut angle.
• For a fairly full hit, with a ball-hit-fraction greater than 3/4, the CB will deflect about 3-times the cut angle (see where the CB goes for different cases).
• For a fairly thin hit, with a ball-hit-fraction less than 1/4, the CB will deflect about 70-75% (about 3/4) of the angle between the aiming line and the tangent line (see where the CB goes for different cases).- The optimal tip height for speed control is 20% of the radius above center (see optimal tip height for speed control).- With a full-hit rolling CB shot, the CB travels about 1/7 the distance of the OB after impact (see ball travel distances).
• With a rolling-CB half-ball hit, the CB and OB separate at close to same speed and same angle (see speed control article).
• With a 45-degree-anlge stun shot, the CB and OB separate at the same angle and distance (see speed control article).
• The miscue limit is half of the cue ball's radius from the center, which is the width of the stripe on a striped ball (see "tips" of English articles).
• FHE and BHE can be used to compensate aim for squirt and swerve when using English.
• When playing a safety in 9-ball, try to leave the OB away from a cushion (see "big ball" effect).
• Faster speed can help bank shot accuracy and consistency (see advantages of fast speed).
• For rolling-ball kicks or banks, the through-diamond aiming system is very reliable.
• With shallow-angle kicks, the contact-point mirror system can be very effective.
• For cross-corner bank shots, it is very important to know how to detect and avoid double kisses.
• Bob Jewett's two-times-fuller and ten-times fuller systems are useful to aim frozen carom and kiss shots.
• Maximum CIT, with no English, occurs with slow speed at about a 1/2-ball hit (see maximum throw).
• Maximum SIT occurs occurs with slow speed and about 50% English (see maximum throw).
• Maximum throw, under typical conditions, is about 1 inch per foot of CB travel, which is about 5 degrees.
• Gearing outside English can be used to eliminate throw, but this might not be the best approach for all people and situations (see using outside English to prevent throw and cling).
• The optimal tip height for a lag shot is 20% of the ball radius above center (see lag shot).
• Knowing where different balls tend to go in a 9-ball rack can be useful to know (see pattern racking strategy).
• In 8-ball, a 2nd-ball break from side can be used to make the 8-ball on the break.
• If you use a break cue with a natural pivot length well matched to your bridge length, stroking errors will not affect your accuracy (see pivot-length article).
• For best jump results, aim between the center of the CB and resting point on the cloth (see jump shot article).
• The Coriolis aiming system for masse shots can be very effective.

Enjoy,
Dave

PS: In case you haven't noticed, I love "rules of thumb!"

more awesomeness!!!!!

 

[dr_dave]

90 Degree Rule – Dave Alciatore
The first and most well-known reference line is the tangent line predicted by the 90 degree rule. For a stun shot (aka a “stop shot at an angle”), where the cue ball is sliding with no top or bottom spin at object-ball impact, the cue ball will head exactly in the tangent line direction, which is perpendicular to the object-ball direction.

Can somebody please explain this better to me or make a diagram?

FYI, instructional articles (with illustrations) and video demonstrations of this important principle can be found here:

90 degree rule resource page​

I hope that helps,
Dave

 

[dr_dave]

From Grady for judging whether there is a kiss or not on certain 'cross the face' bank shots: "If you can shoot the cue ball past the object ball straight into the pocket, no kiss..."

Heard many times on Accu-Stats commentary. That's the best summary I can provide. Perhaps someone else can elaborate if that is not clear or inaccurate.

RIP Professor

The double-kiss line is usually closer to the facing of the pocket, per the demonstration here:

NV B.23 - Cross-corner bank shot double kiss detection and avoidance​

Regards,
Dave

 

[Bob Jewett]

A simpler (for me) way to visualize this:

The CB's rebound angle off the rail will exceed 90 degrees by only 1/4 of what its "mirror" rebound angle (without the OB) would. ..

While this is sometimes close, it differs by the difference between the tangent of the angle and the angle. So, if you use the 1/4 the angle for the 45-degree cut, the prediction is that the outbound angle is 11.25 degrees (45/4) which has a tangent of .2 rather than .25. If you come in at the 2:1 slope in the diagram shown above, the angle in is 63 degrees away from the perpendicular to the cushion. 63/4=15.8 degrees which is a tangent of 0.28. The 1/4 slope method predicts a tangent of 0.5 for that approach.

For small angles, the tangent is equal to (or directly proportional to) the angle, but for larger angles they diverge. Sometimes this can be fixed up by taking the complementary angles. Usually, the result is more accurate if you work with tangents (ratios of slopes) and not angles.

 

[Patrick Johnson]

Me:

A simpler (for me) way to visualize this:

The CB's rebound angle off the rail will exceed 90 degrees by only 1/4 of what its "mirror" rebound angle (without the OB) would.

Bob:
While this is sometimes close, it differs by the difference between the tangent of the angle and the angle. So, if you use the 1/4 the angle for the 45-degree cut, the prediction is that the outbound angle is 11.25 degrees (45/4) which has a tangent of .2 rather than .25. If you come in at the 2:1 slope in the diagram shown above, the angle in is 63 degrees away from the perpendicular to the cushion. 63/4=15.8 degrees which is a tangent of 0.28. The 1/4 slope method predicts a tangent of 0.5 for that approach.

For small angles, the tangent is equal to (or directly proportional to) the angle, but for larger angles they diverge. Sometimes this can be fixed up by taking the complementary angles. Usually, the result is more accurate if you work with tangents (ratios of slopes) and not angles.

Actually, that's how I mostly do it, since it's easier to divide the downtable distance than the angle. I think of it as dividing the angle, but (especially over 45 degrees) that's obviously not the case. Thanks for the clarification.

pj
chgo

 

[Jal]

....Rule of thumb for slight angle cuts with a soft rolling cb? Say you are shooting an almost straight in to the corner from short distance. You need a breakout or position on a ball on the short rail -it seems that the rolling cb moves down approximate 3x cut angle line after contact.

Is this about right or does it just seem that way? It seems fairly reliable on slight angle cuts.

Earlier I said "I had to look up the answer to your observation (3X the cut angle) on Dr. Dave's VEPS.... I will say your figure (3X) is fairly close to his."

Actually, according to Dr. Dave's technical article TP B-13 (page 4), which takes into account friction and the inelasticity of the collision, your 3X factor is not merely "fairly close," but spot on!

Nice call and thanks again to Dr. Dave.

Jim

 

[Saturated Fats]

There must be more of these..

Anyone else have something to contribute?

 

[Pushout]

Great thread! One of the best in a long, long time!! I'll kick the cobwebs around and see if I can come up with anything not already posted.

 

[bbb]

i didnt read anything except the title
my advice is dont get your thumbs broke

 

[Antfarm]

My Rules of Thumb.

1. If you don't make the shot, you don't keep shooting and therefore, no aiming system or knowledge of angles mattered anyway. Make your shots.

2. If you can't play defense, you will never beat good players.

3. When playing defense, the path/position of the cue ball is what you should be focusing on, not the object ball.

4. 75% of the time, you need nothing more than 1 tip of follow, draw or a straight center ball shot. Avoid left and right if you can.

5. If you can't get position off ball in hand, you shouldn't be playing competitively yet. Defense is position.

6. If you don't play the player, you are going to get beat by the player in the long run.

7. If you aren't comfortable with your equipment/environment, it is going to negatively affect your game. The same holds true to your mood.

8. If you suck, ask for help. Practice.

9. If you miss ball in hand on an open shot, you suck. (I have sucked in the past myself)

10. Play the game like it's a game, not life or death. Shake a persons hand after he/she beats you like a good sportsman should.

That's my rule of thumbs that I play by. The actual shooting to me is arbitrary. If I do these rules, I have fun and I enjoy playing. That's what playing pool is all about to me.... having fun and enjoying it because I love the game.

R,

Greg

 

[Maniac]

9. If you miss ball in hand on an open shot, you suck. (I have sucked in the past myself)

I cannot tell you how many times I've seen bona fide professionals do just that..........and THEY do not suck!!!

Maniac (happens to any and all of us, from the best to the worst of players)

 

[Antfarm]

I'm not saying that you suck overall. I'm just saying that it is just about the worst thing and you feel like you totally suck when you miss ball in hand on an easy open shot.

Sorry, I should have clarified!

R,


Greg

 

[VIProfessor]

I really like one of Cornerman's 8-ball RoT's. Unless you can get there with pretty much a stop-stop pattern or the 8-ball can be made from anywhere, avoid using a side pocket shot as your key ball. There are too many ways to end up having to go around the table.

Hey Fred! What's up, bro? How did the weather treat you?

 

[PGHteacher]

This advice mostly comes from George Fels:

Become a minimalist: don't "skid" the CB when you can roll it someplace, the best shot is the softest one that will accomplish what you want to do, don't use english or action if you don't have to, move the CB as little distance as you can to accomplish what you want to, don't use a rail if you don't have to, use as few rails as you can.

Shoot for the closest whole pocket:That's the biggest target.

Remember what rules of thumb are for:They are not meant to be adhered to in every situation, they are meant to help you when you are having trouble deciding what to do and to teach you how generally to play the game, there is a hierarchy in rules of thumb and you need to decide sometimes which one to break, you can break any rule of thumb at anytime as long as you have a very good reason to do so, "that's how I saw it" or "it looks cool" are not good enough to break a rule of thumb.

 

[Saturated Fats]

Bump to get some more RoTs. Thanks everyone!

 

[JoeyA]

Excellent thread!

 

[Lock N Load]

While reading through some older Bob Jewett BD columns, I noticed that Bob uses a number of "rules of thumb". I find them very helpful and decided to gather as many of these together as I could. Below are fifteen rules of thumb that I gathered from various places. The names that I have credited for these represent the first place I saw them - not necessarily an original source. I don't really know the original sources for these.

If not stated clearly, please correct them as you see fit or ask for clarification, if necessary. I hope you find them helpful too. Would you like to add any to the pool of knowledge?

90 Degree Rule – Dave Alciatore
The first and most well-known reference line is the tangent line predicted by the 90 degree rule. For a stun shot (aka a “stop shot at an angle”), where the cue ball is sliding with no top or bottom spin at object-ball impact, the cue ball will head exactly in the tangent line direction, which is perpendicular to the object-ball direction.

Avoiding Double Kisses – Freddie The Beard
When the balls line up on a straight line to the middle of the FACING of the corner pocket (the facing on the long rail), the bank is a dead kiss. It is extremely difficult to beat the kiss when the balls are on a line to the middle of the FACING.
When the balls line up on a straight line to the MIDDLE of the back of the POCKET, there is no kiss.
When the cue ball and an imaginary ball at the contact point for the bank are on a line to the center of the pocket, there is a dead kiss if you use follow with no English.
These kisses are usually easy to evade by using English or draw to send the cue ball on a non-kiss path.
The aim on the object ball must be adjusted to allow for the ball action needed for a non–kiss bank.

Throw When Balls Are Close – Bob Jewett
If the balls are a quarter-inch apart, there is no throw or cut, no matter how you hit them.

6:1 Rolling Cue Ball Ratio – Bob Jewett
The ratio of about 6:1 is a useful rule of thumb when playing soft position. Suppose the object ball is six diamonds from a pocket, and you want the cue ball to follow straightforward not more than about one diamond after the collision. If you just get the object ball to the pocket — six diamonds of travel — the (rolling) cue ball will roll forward about one diamond. Another way to state this is that on a full, soft follow shot, the cue ball will go forward one ball for each diamond the object ball travels. At a later time, Bob gives the ratio as 7:1.

Ball in Hand – Bob Jewett
With ball in hand, you should never place the cue ball for a draw shot.

Two Rail Banking – Bob Jewett
If a ball is sent along roughly a 45-degree angle between the short rail (first) and the long rail (second) it will go close to two rails into the corner.

45 Degree Rule – Dave Alciatore
If the CB rolls into the short rail at roughly a 45-degree angle, it will head fairly close to the center of the table after contacting the long rail.

Importance of Rolling Cue Ball Through the Center of the Table – Danny Basavich
A cue ball rolling through the center of the table for position cannot scratch unless coming directly from the direction of a pocket (or first hitting at least one more rail). Stated differently, unless the cue ball is rolling straight from a pocket, it cannot scratch directly in a pocket after passing through the center of the table.

Banking Frozen Object Balls – Bob Jewett
If the cue ball is straight out from the frozen object ball, the ball has to be at least one diamond up the rail from the target pocket for the bank to be possible using all techniques.

Half Ball Carom (30 Degree Rule) – Dave Alciatore
If the object ball cut angle is anywhere from 15 degrees to 45 degrees, a rolling cue ball is deflected by very near 30 degrees from its original path.

Equal Distance – Bob Jewett
After a half ball hit with a rolling cue ball, the cue ball and object ball will travel a similar distance.

Shortening Banks By Hitting Firm and Full – Bob Jewett
Banks that are dead using a mirror system (for example from diamond 3 to diamond 1.5), can be shortened by hitting full and firmly (for example, diamond 3 to diamond 1). The idea is if you can get the shot to match the mirror system by subtracting 1 from the cue ball's location, the bank is "on" for the system. So, if you subtract 1 from cue ball's 3, you get 2-to-1, which is a standard mirror bank. Therefore it is “on” for a full, firm bank.

Cue Ball Deflection On Nearly Full Shots – Bob Jewett
If you cut the object ball just a little to one side (3/4 ball or fuller), a rolling cue ball will be deflected about three times the angle to the other side. For example, a five degree cut to the left will result in the cue ball being deflected to the right about 15 degrees.

Path of Rolling Cue Ball After Hit – Shawn Putnam
This is a system to predict the direction the cue ball will go on a rather full hit (about ¾ ball or fuller) after rolling into the object ball with follow. To send the cue ball in a particular direction, visualize the spot on the far side of the object ball that points to where you want the cue ball to go and then aim the cue ball to that point on the far side of the object ball.

Sidespin/Squirt Ratio – Bob Jewett
Two tips of English will produce twice the squirt angle of one tip.

Hey Fats,
This is a very good thread!
Many Regards,
Lock N Load.

 

[Lock N Load]

My Rules of Thumb.

1. If you don't make the shot, you don't keep shooting and therefore, no aiming system or knowledge of angles mattered anyway. Make your shots.

2. If you can't play defense, you will never beat good players.

3. When playing defense, the path/position of the cue ball is what you should be focusing on, not the object ball.

4. 75% of the time, you need nothing more than 1 tip of follow, draw or a straight center ball shot. Avoid left and right if you can.

5. If you can't get position off ball in hand, you shouldn't be playing competitively yet. Defense is position.

6. If you don't play the player, you are going to get beat by the player in the long run.

7. If you aren't comfortable with your equipment/environment, it is going to negatively affect your game. The same holds true to your mood.

8. If you suck, ask for help. Practice.

9. If you miss ball in hand on an open shot, you suck. (I have sucked in the past myself)

10. Play the game like it's a game, not life or death. Shake a persons hand after he/she beats you like a good sportsman should.

That's my rule of thumbs that I play by. The actual shooting to me is arbitrary. If I do these rules, I have fun and I enjoy playing. That's what playing pool is all about to me.... having fun and enjoying it because I love the game.

R,

Greg

Ant Farm,
Very good!
Many Regards,
Lock N Load.

 

[Cornerman]

I really like one of Cornerman's 8-ball RoT's. Unless you can get there with pretty much a stop-stop pattern or the 8-ball can be made from anywhere, avoid using a side pocket shot as your key ball. There are too many ways to end up having to go around the table.

Hey Fred! What's up, bro? How did the weather treat you?

Hey Rudy! The Florida weather is treating me just fine!!!

Freddie

 

[Tramp Steamer]

When playing One Pocket, never bring a ball down table if you don't need it. For instance: The score is 7 to 4 (your favor) and there are four balls left on the table. Two are up table and two are down. If you go for one of the up table balls (a long rail bank, say) and miss, you run the risk of your opponent going out. When that happens it's like the late great Willie Jopling used to say. "Racky Tacky". :smile: