Cue Ball Spin

Andrew Manning said:
I'll try to help:
SNIP

The diagram (overhead look) makes it hard to tell, but let's just assume I positioned the 9 such that if you hit the CB without english and just barely missed the 9 (cleared it by less than a hair's width), the 8 will not pocket in the corner. A soft stroke with 3:00 english will pocket it, due to throw.

-Andrew
Click to expand...

Thanks, Andrew, for the drawing. Quite effective. I agree with Bob Jewett that the way to make this bullet-proof is to make a three ball ensemble, which was the idea in my post.

Thanks again.

Flex
 
bank shot requiring throw and spin transfer

Bob Jewett said:
The skeptic asks: How can you be sure that it is not transferred spin that's helping to make the bank rather than throw? And, maybe there's a little swerve around the blocker.
Click to expand...
FYI, NV A.21 shows a similar shot. I demonstrate what happens with various amounts of cut angle, swerve, throw, and spin transfer.

My March '07 article has illustrations and explanations of the effects.

Regards,
Dave
 
throw and spin-transfer skeptics

Scott Lee said:
I guess you'll have just call me a skeptic.:D
Click to expand...
Scott,

Please explain your skepticism. Do you think throw and/or spin transfer are not important in a shot like this (e.g., see NV A.21)? Scott, I'm not asking this to be disrespectful. I just want to know what you mean when you say you are skeptical.

For people that doubt the existence or importance of throw and/or spin transfer, here are some things to look at and think about:

- See my August '06 through July '07 BD articles dealing with throw and spin transfer. I provide many illustrations, video demos, and experimental data explaining all of the effects and why they are important.

- See NV A.21 and my March '07 article. The bank example demonstrated and explained in that clip and article provides pretty convincing evidence of the effects.

- See HSV A.66. This super-slow-motion clip provides a visual demonstration of the effects.

- For the physics nerds out there, TP A.27 provides a physics-based mathematical proof of both effects.

Also, lots of answers to frequently-asked questions about throw and spin transfer can be found here:
http://billiards.colostate.edu/threads/throw.html

If people are still skeptical after checking out of these resources, then I give up.

Regards,
Dave
 
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throw tomatoes

pdcue said:
You say tomatoe - Mike Siegel says tamahtoe.
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People who understand throw and spin transfer say and write "tomato" ... because they like being correct. ;)

Regards,
Dave
 
low-squirt spin benefit is negligible

Patrick Johnson said:
What do you think is the percentage increase in "effective tip offset" for typical low-squirt vs. high-squirt cues? I imagine it's very low...
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Your imagination is quite correct. Per my September '07 article, a common low-squirt cue has a squirt angle of about 1.8 degrees at close to maximum tip offset, as compared to 2.5 degrees for a typical regular-squirt cue. So a low-squirt cue offers only about 30% less squirt than a typical regular-squirt cue.

Per Diagram 3 in my December '07 article, if you calculate the effective offsets using the squirt angles above, the percentage change in effective tip offset is less than 0.1%!!! So I think it is safe to say this effect is negligible.

Now, when comparing cues and/or tips, it is important that the actual tip offset is the same for both. If the tip size and shape are different, and one uses "tips of English" as a measure, perceived tip offset can be very different than actual offset, resulting in significant differences in the amount of spin. See my January '08 and July '06 articles for more information (and illustrations).

Regards,
Dave
 
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Doc Dave:
...a low-squirt cue offers only about 30% less squirt than a typical regular-squirt cue
Click to expand...

That means the "natural" pivot point (disregarding swerve) for a typical low-squirt cue is only 30% longer than the NPP for a regular-squirt cue, right? In other words, if a regular-squirt cue's NPP is, say, 15 inches from the tip, then a low-squirt cue's NPP is only 15 x 1.3 = 19.5 inches from the tip?

To me that's surprisingly close. I believe most players (including myself) have the impression that a low-squirt cue's NPP is more like twice as far from the tip, maybe even more!

pj
chgo
 
Patrick Johnson said:
That means the "natural" pivot point (disregarding swerve) for a typical low-squirt cue is only 30% longer than the NPP for a regular-squirt cue, right? In other words, if a regular-squirt cue's NPP is, say, 15 inches from the tip, then a low-squirt cue's NPP is only 15 x 1.3 = 19.5 inches from the tip?

To me that's surprisingly close. I believe most players (including myself) have the impression that a low-squirt cue's NPP is more like twice as far from the tip, maybe even more!

pj
chgo
Click to expand...

Is pivot point LINEARLY related to squirt angle for a given tip offset/stroke speed? If not, then your 15" X 1.3 is not necessarily a valid calculation.

I don't feel like doing the geometry myself, so can anyone clear that up?

-Andrew
 
squirt angle and pivot length relation

Andrew Manning said:
Is pivot point LINEARLY related to squirt angle for a given tip offset/stroke speed? If not, then your 15" X 1.3 is not necessarily a valid calculation.

I don't feel like doing the geometry myself, so can anyone clear that up?
Click to expand...
TP B.1 has the geometry (and an equation) that relates squirt angle to natural pivot length (NPL). Page 3 of the document and my November '07 article compare experimental and calculated values. For the regular cue with a squirt angle of 2.5 degrees, the NPL is about 12 inches. For the low-squirt cue with a squirt angle of 1.8 degrees, the NPL is about 20 inches. These NPLs are not taking throw into consideration (see the article for more info).

Regards,
Dave
 
Is pivot point LINEARLY related to squirt angle for a given tip offset/stroke speed?
Click to expand...

Yes, even though I compared the wrong things. . "30% more squirt" would mean a low-squirt PP 30% longer, but "30% less squirt" (as it was described) means a high-squirt PP 30% shorter. The linear progressions are:

low-squirt cue 30% less squirt = high-squirt PP 30% shorter
low-squirt cue 20% less squirt = high-squirt PP 20% shorter
low-squirt cue 10% less squirt = high-squirt PP 10% shorter

high-squirt cue 30% more squirt = low-squirt PP 30% longer
high-squirt cue 20% more squirt = low-squirt PP 20% longer
high-squirt cue 10% more squirt = low-squirt PP 10% longer

pj
chgo
 
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dr_dave said:
People who understand throw and spin transfer say and write "tomato" ... because they like being correct. ;)

Regards,
Dave
Click to expand...

Too many inside jokes for you?

Song lyric:
'You sat tomato,<long A>, I say tomato<Sort A>

Dal Quale spelled potato
<the next line in the song> ending in an E.

Mike Siegel says there is no such thing as throw.

All of which may be that Scott agrees - ergo the question
about 'spin'

Next time I ask Scott a question I'll be sure to warn you
if I'm being cute first.

Dale
 
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tomato jokes

pdcue said:
Too many inside jokes for you?

Song lyri:
'You sat tomato,<long A>, I say tomato<Sort A>

Dal Quale spelled potato
<the next line in the song> ending in an E.

Mike Siegel says there is no such thing as throw.

All of which may be that Scott agrees - ergo the question
about 'spin'

Next time I ask Scott a question I'll be sure to warn you
if I'm being cute first.

Dale
Click to expand...
I don't think I missed your joke. I actually know that song quite well. I saw "When Harry Met Sally" recently and I have the Harry Connick Jr. CD containing the song. I was kind of making a joke in return (see the winking smiley face in my original post) ... while trying to make a point.

I know about Mike Siegel's views on throw. I read all of the articles he and Bob Jewett wrote back and forth in BD many years ago when Bob was trying to convince him and others throw and spin transfer exist. I have also written many articles and filmed lots of video demos dealing with these topics. There still seems to be a fair amount of skepticism and misinformation out there.

I'm new to this forum, so if I miss some of your inside jokes, I apologize. I'm sure I'll learn over time.

Regards,
Dave
 
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