Do you adjust your aim for different spins and speeds?

Patrick Johnson said:
This is exactly what your shaft's "pivot length" tells you: the cue ball will be [tip offset] off line for each [pivot length] it travels.

So if you're using maximum sidespin (say your tip offset = 1/2"), and your pivot length = 12" (for example), then the cue ball will be 1/2" off line for each 12" that it travels.

If you think about it, this also explains why pivoting at the pivot point to apply sidespin compensates for squirt (if there's not much swerve).

pj
chgo

P.S. I've used 12" as the assumed pivot length in this example so it matches Dave's estimate (I think it's a fairly common pivot length), but if your pivot length is longer or shorter, then the amount of squirt will change proportionately. For instance, if your tip offset = the same 1/2" but your pivot length = 24" (a lower squirt shaft), then the cue ball will be 1/2" off line for each 24" of travel (half as much squirt). And if your pivot length = 6" (a higher squirt shaft), then the cue ball will be 1/2" off line for each 6" of travel (twice as much squirt).
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Well explained Patrick!

My cue's pure pivot point is about 12 inches, but the Effective pivot point, which takes into account sqwerve, can be as high as 20 inches on long slowish shots. For the majority of shots it is 14 to 16 inches.

For that reason I wouldn't want to use a very low deflection shaft.

Colin
 
cue natural pivot length

Patrick,

Excellent post!

If people want to learn more about natural pivot length, my November '07 article has some good illustrations and explanations. The article also has an easy-to-follow procedure to measure the natural pivot length of a cue.

Regards,
Dave

Patrick Johnson said:
This is exactly what your shaft's "pivot length" tells you: the cue ball will be [tip offset] off line for each [pivot length] it travels.

So if you're using maximum sidespin (say your tip offset = 1/2"), and your pivot length = 12" (for example), then the cue ball will be 1/2" off line for each 12" that it travels.

If you think about it, this also explains why pivoting at the pivot point to apply sidespin compensates for squirt (if there's not much swerve).

pj
chgo

P.S. I've used 12" as the assumed pivot length in this example so it matches Dave's estimate (I think it's a fairly common pivot length), but if your pivot length is longer or shorter, then the amount of squirt will change proportionately. For instance, if your tip offset = the same 1/2" but your pivot length = 24" (a lower squirt shaft), then the cue ball will be 1/2" off line for each 24" of travel (half as much squirt). And if your pivot length = 6" (a higher squirt shaft), then the cue ball will be 1/2" off line for each 6" of travel (twice as much squirt).
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The only time I do is when hitting slowly with spin...

Colin Colenso said:
Not many people are aware that the angles the OB takes after impact varies considerably according to the speed of the CB and the spin on it.

Recently, with the assistance of Dr. Dave, I put together a series of plots that give a visual representation of this variation in OB throw.

Left edge is 100% Inside English, Right edge is 100% Outside English.
Top is 100% forward spin, bottom is 100% bottom spin. The center represents a sliding cue ball.

The values are contrasted against the angle the OB takes on a soft-medium speed (8km/h ~ 5mph) natural rolling shot, not the line through centres, because we rarely actually want to aim at this contact point.

The units are in inches per yard.

2b6xx0.jpg

Slow Speed 1/8th Ball Shot. 4km/h ~ 3mph
2zr0xtk.jpg

Medium Speed 1/8th Ball Shot. 12 km/h ~8mph
dgqbmg.jpg

Very High Speed 1/8thBall Shot. 36 km/h ~22mph​

The orange colors indicate that the OB will be directed along a thicker line (undercutting), while the bluish shades indicate that the OB will be directed to a thinner line (overcutting).

Some things to notice are:
1. A soft stun shot make cause you to undercut the shot by around 4 inches if the OB is just 3 feet from the pocket.

2. For soft and medium speed shots, heavy Outside English results in overcutting of up to 5 inches over 3 feet.

3. High power stun, follow or draw shots cause slight undercutting.

So my questions to members are:
1. Were you aware of any of this?
2. Do you ever make conscious adjustments for these changes in throw?
3. Do you think you miss often due to not taking into account these changes in throw?

Feel free to add any other thoughts, comments or questions.

Colin
Here is the Legend for those that requested it. Units are inches per yard.​
1znsj5x.jpg
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I only adjust my aim (aside from using BHE) when hitting slow shots with spin and when I do that it is almost invariably because I don't have the whole ball and I need to throw the ball into the hole with sidespin. I may VERY rarely do it for position if I need to either create angle that isn't there or get less angle than is there.

Jaden.
 
Colin Colenso said:
There's no doubt that over thinking initially makes the game harder, but I look at it more like an air plane pilot. Years ago pilots flew mostly by instinct, today, in most circumstances the plane can fly more accurately using auto-pilot, which has over the years found ways to predict and adjust to the many variables used in flying a plane.

So if an adjustment method is developed for certain areas of pool aiming, then these factors can become like auto-pilot for the pilot that has learned that system well.

There is always plenty of scope for a player to use imagination, intuitive adjustments, touch and other variables that affect playing performance.

Colin
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My point was ...that on the other side of your picture is your 'inner mind' and 'it' doesn't need to know #'s or think in words and 'it' can do things that the 'ego' centric mind could never figure out. There is a place for both, but I prefer to get out of the way of ego (knowledge) and embrace intuition (knowing). There is more power there than any of us can imagine.

May the force be with you...........:grin: :grin:

td
 
There is a place for both, but I prefer to get out of the way of ego (knowledge) and embrace intuition (knowing).
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There's also a time for both. Your intuition (your "feel") doesn't just appear magically, you have to build it - and building it by learning and applying that knowledge during practice (infusing experience with knowledge) is the most efficient and effective way.

It's probably true (at least for most) that "getting out of the way" of your intuition is necessary in order to allow your knowledge and experience to fully integrate and be put to its highest and best use during play/competition.

pj
chgo
 
Colin Colenso said:
The values are contrasted against the angle the OB takes on a soft-medium speed (8km/h ~ 5mph) natural rolling shot, not the line through centres, because we rarely actually want to aim at this contact point.
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This got me at first glance because I'm used to thinking in terms of the LOC! Sure made all that over-cutting with no english look bizarre :)
1. Were you aware of any of this?
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Yes. I love the technical details of pool and billiards, which definitely puts me in the over-thinking analytical player category. :)
2. Do you ever make conscious adjustments for these changes in throw?
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Yes. I have created a comprehensive system that merges pool and 3-cushion billiards that was built from the ground up using physics, geometry and a good understanding of high-level play in both disciplines. I figured out how to merge my technical knowledge with my physical skill in a practical way at the table, and I intend to publish what I've discovered when I can finish writing it up. Feel-only players will hate it, of course, but anyone with a slightly geeky side will probably enjoy it.
3. Do you think you miss often due to not taking into account these changes in throw?
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I always take them into account, but in general it isn't always so easy to determine what caused a miss. Usually, I feel it's from stroking errors. For example, if I'm not accounting for my cue's deflection properly, then that will surely cause missing. I also tense my wrist sometimes which causes my tip to move from its intended aim point before contact. When I'm stroking accurately, however, I don't miss that much. :)

The exciting thing about having a strong model is that I've been able to minimize my practice time required to maintain a high level of play (for a non-professional). That was my main goal all along, since I only play once or twice a week. When I do practice, it's usually stroking and speed control drills.

The bad thing is that it can be mentally fatiguing to do so much thinking during play when others are conserving resources by coasting on auto-pilot. I'm ok with that. I work out to improve my stamina, and I know all the thinking will get easier and faster over time anyway as I use and refine the material more. For me, it's much more satisfying than trial and error and/or rote shot memorization!

Robert
 
Colin,

I enjoyed the contour plots. I do something similar in excel with some of my material to get a feel for certain trends.

What do you consider 100% spin in your charts? I guess I'm asking what is your assumed miscue limit?

Robert
 
Colin Colenso said:
Yogi is a humorous fellow, but I prefer the words of Lord Kelvin
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Lord Kelvin wasn't paying attention to the distinction between knowing that and knowing how. Knowing how is much more important to playing pool well than is knowing that.
 
And then there is adjusting for distance and elevation and thickness of hit.

IMO there are too many variables to take into consideration during actual competitive pressure.

Edit: equipment and conditions.
 
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Robert Raiford said:
Colin,

I enjoyed the contour plots. I do something similar in excel with some of my material to get a feel for certain trends.

What do you consider 100% spin in your charts? I guess I'm asking what is your assumed miscue limit?

Robert
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Robert,

I should check the exact 100% spin rates definition with Dr. Dave as he creates the original data. My guess would be it represents the spin:speed ratio of a rolling ball, which appears to be pretty close to the maximum spin:speed ratio obtainable for extreme english shots (not masse shots).


Colin
 
lewdo26 said:
And then there is adjusting for distance and elevation and thickness of hit.

IMO there are too many variables to take into consideration during actual competitive pressure.

Edit: equipment and conditions.
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There is no real adjustment based on elevation. If you have to elevate, you'll need to guess the adjustments, as all players do.

The system has quite a bit of complexity, but considering that many players already find BHE useful, by them learning new or more accurate adjustments on new shots each day, they are gradually expanding their capabilities.

I'd say that with a month of steady study and practice, a player could have become comfortable with executing the system parameters in competition for 90+% of shots where they'd consider using BHE with adjustment as a shot option.

That will be too much effort for most, but I think those who put in the work will be very pleased they did.

Colin
 
percentage spin

Colin Colenso said:
I should check the exact 100% spin rates definition with Dr. Dave as he creates the original data. My guess would be it represents the spin:speed ratio of a rolling ball, which appears to be pretty close to the maximum spin:speed ratio obtainable for extreme english shots (not masse shots).
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100% refers to maximum tip offset, which corresponds to the tip contact point at the miscue limit (generally accepted be be 1/2 of the CB's radius). I have a useful illustration on page 5 in TP B.3. I also have good illustrations and explanations of "tips of English" and "percentage English" in my July '06 and January '08 articles. At 100% follow, there is actually overspin (more topspin than the forward roll amount).

Regards,
Dave
 
dr_dave said:
100% refers to maximum tip offset, which corresponds to the tip contact point at the miscue limit (generally accepted be be 1/2 of the CB's radius). I have a useful illustration on page 5 in TP B.3. I also have good illustrations and explanations of "tips of English" and "percentage English" in my July '06 and January '08 articles. At 100% follow, there is actually overspin (more topspin than the forward roll amount).

Regards,
Dave
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Thanks for the input Dave. I will try to make sure to clarify such things when describing the system in full. For most practical purposes / testing / visualization my generalizations seem to work fine.

I assume you've seen Mike Page's video showing how difficult it was to demonstrate follow overspin. That's one reason I assumed the ratios were pretty close.

Colin
 
dr_dave said:
At 100% follow, there is actually overspin (more topspin than the forward roll amount).

Regards,
Dave
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Dave,
I may have perused those papers too quickly, but I couldn't see where it compared natural roll to maximum overspin.

What % would natural roll represent? 90-95%

Colin
 
natural roll spin percentage

Colin Colenso said:
I may have perused those papers too quickly, but I couldn't see where it compared natural roll to maximum overspin.

What % would natural roll represent? 90-95%
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TP A.25 relates tip contact-point offset to spin-rate factor (SRF) to percentage English (PE) or spin. With natural roll, SRF = 1 and PE = 80%.

Also, the diagram on page 5 in TP B.3 illustrates graphically where the natural roll point is on the contour plot square.

Regards,
Dave
 
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dr_dave said:
TP A.25 relates tip contact-point offset to spin-rate factor (SRF) to percentage English (PE) or spin. With natural roll, SRF = 1 and PE = 80%.

Also, the diagram on page 5 in TP B.3 illustrates graphically where the natural roll point is on the contour plot square.

Regards,
Dave
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Colin, this is reflected in the common advice to strike the cueball at .4 radius above center to achieve instant natural roll (.4 radius = .8 maximum follow).

[BTW, the same advice applies to sidespin tip offset for getting "neutral running english", except it's .4 of the distance to the "opposite-of-rail/ball contact point".]

pj
chgo
 
Patrick Johnson said:
Colin, this is reflected in the common advice to strike the cueball at .4 radius above center to achieve instant natural roll (.4 radius = .8 maximum follow).

[BTW, the same advice applies to sidespin tip offset for getting "neutral running english", except it's .4 of the distance to the "opposite-of-rail/ball contact point".]

pj
chgo
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I see. I remember Robert Byrne using a similar number to get the CB rolling smoothly.

It's interesting that Mike's video couldn't demonstrate overspin. His set up looked quite sensitive to indicating overspin if it was there.

Colin
 
overspin video and info

Colin Colenso said:
It's interesting that Mike's video couldn't demonstrate overspin. His set up looked quite sensitive to indicating overspin if it was there.
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Could you please provide a link to the video? I demonstrate overspin in HSV B.26, and talk about it in more detail here:


Regards,
Dave

edited: OOPS, you must have sent your link message while I was writing this post. Thanks.
 
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