Low deflection rant

[cheapcues.com]

The biggest problems are:
- The cue isn't level, so swerve is a factor, and swerve is affected by ball and cloth conditions, which can change over time. Also, cues producing different CB speeds (due to weight and/or tip efficiency differences), will create different amounts of swerve, which will affect results.
- The CB hits an OB, so throw is a factor, and throw varies with ball conditions and speed. Therefore the cue weight and tip efficiency, which affect speed, and randomness of ball-to-ball contact point properties and cleanliness can affect the results.
- The shape of the tip has an effect. A rounder tip will create more tip offset (at the tip contact point) which affects the amount of English, which affects the amount of squirt, swerve, and throw. This problem is easy to avoid by shaping each tip with a consistent tool before testing, but I'm not sure this was done.

There are way too many variables in the Meucci experiment. The goal is to measure squirt (CB deflection) produced by different shafts for a given tip offset, but that's not exactly what is being measured.

Regards,
Dave

Thank you Dave.

Sorry I have been busy today and I wanted to re-watch the video and haven't had time to do it yet. I think Dave pretty much hit the nail on the head of why I have a problem with Bob's experiment. Instead of just hitting a cue ball down to the end of the table and measuring where it hits, he puts an object ball in the way and measures where the object ball hits the rail. There are so many factors as Dave mentions that will effect where that ball hits the rail- most notable are the speed of the shot and the amount of tip offset, which will effect the swerve an the throw as well as the squirt. I can only conclude from watching that video that Bob dialed in the parameters of the experiment so that his products would yeild the best result (OB hiting the foot rail as close to the center line as possible). I'm still going to re-watch the video and see if I can shed some more light or explain better, or perhaps I'll even change my mind.

 

[GetMeThere]

The biggest problems are:
- The cue isn't level, so swerve is a factor, and swerve is affected by ball and cloth conditions, which can change over time. Also, cues producing different CB speeds (due to weight and/or tip efficiency differences), will create different amounts of swerve, which will affect results.
- The CB hits an OB, so throw is a factor, and throw varies with ball conditions and speed. Therefore the cue weight and tip efficiency, which affect speed, and randomness of ball-to-ball contact point properties and cleanliness can affect the results.
- The shape of the tip has an effect. A rounder tip will create more tip offset (at the tip contact point) which affects the amount of English, which affects the amount of squirt, swerve, and throw. This problem is easy to avoid by shaping each tip with a consistent tool before testing, but I'm not sure this was done.

There are way too many variables in the Meucci experiment. The goal is to measure squirt (CB deflection) produced by different shafts for a given tip offset, but that's not exactly what is being measured.

Regards,
Dave

Good. Thanks.

The most illuminating to me is: "Also, cues producing different CB speeds (due to weight and/or tip efficiency differences), will create different amounts of swerve, which will affect results."

I often think about trying to do such tests myself--and the difficulties of repeatability of the equipment. Now I realize that probably the easiest thing to do (at least for one variable) is MEASURE speed (of whatever), and ignore tests outside the speed range you consider useful for the test. (i.e., instead of trying to produce perfect MACHINERY, one can choose to collect only perfect "data" from imperfect machinery)

 

[GetMeThere]

I can only conclude from watching that video that Bob dialed in the parameters of the experiment so that his products would yeild the best result (OB hiting the foot rail as close to the center line as possible). I'm still going to re-watch the video and see if I can shed some more light or explain better, or perhaps I'll even change my mind.

It's known and understood that reducing mass near the tip reduces deflection. There's NO KNOWN REASON why merely laminating shafts (Meucci black dot) should make them deflect so much less than "hollow" LD shafts.

When an unexpected (even contrary) result arises, one needs to give some consideration to the experimental setup. I agree that SOMETHING must be wrong with Meucci's experiments--knowing exactly what that is would be useful (for me--because I would sometime like to do some similar things).

 

[dr_dave]

Good. Thanks.

The most illuminating to me is: "Also, cues producing different CB speeds (due to weight and/or tip efficiency differences), will create different amounts of swerve, which will affect results."

I often think about trying to do such tests myself--and the difficulties of repeatability of the equipment. Now I realize that probably the easiest thing to do (at least for one variable) is MEASURE speed (of whatever), and ignore tests outside the speed range you consider useful for the test.

If you do tests with a perfectly level cue, speed doesn't matter.

Squirt does not depend on speed; and with a perfectly level cue, there is no swerve.

The machine I used for all of my tests had a perfectly level cue.

For more info, see:

"Squirt - Part VII: cue test machine results" (BD, February, 2008)
"Return of the squirt robot" (BD, August, 2008)​

Regards,
Dave

 

[cheapcues.com]

I like broccoli

How can 8-pieces of differing laminates have more radial consistency ?

A straight maple shaft is stiffer in one direction due to the grain of the wood. The 8 piece pie lamination eliminates the grain factor.

How can a hollowed out shaft feel better ?

It just does, to me. Do you like broccoli? I do. If you don't are you going to question how broccoli could taste good?

You can spin the shaft anywhere you want, it will still have the same end-weight and flexibility.

True on end weight, not on flex.

 

[GetMeThere]

If you do tests with a perfectly level cue, speed doesn't matter.

Squirt does not depend on speed; and with a perfectly level cue, there is no swerve.

The machine I used for all of my tests had a perfectly level cue.

For more info, see:

"Squirt - Part VII: cue test machine results" (BD, February, 2008)
"Return of the squirt robot" (BD, August, 2008)​

Regards,
Dave

Right. I wasn't referring to EXACTLY what was being tested (I'm more interested in "stroke" than the "squirt" phenomenon).

I DO want to test under "real world" conditions (cue NOT level), however. In any test I make I will want to be able to make very CLEAR claims about the exact point of CB contact, the angle of the cue at contact, and the speed of the cue.

 

[dr_dave]

Radial consistency is meaningless.
...
I believe Dr Dave even tested this, and showed that the radial orientation had no impact on the outcome of the shot. I may be wrong, but I think he even did the test on a flat laminated shaft, which would theoretically be the worst offender.

What my tests showed is that squirt didn't seem to vary with cue orientation. More info can be found here:

Squirt - Part VII: cue test machine results" (BD, February, 2008)"​

In my view, the advantages a radial laminate offers are improved strength and less chance for warping over time. Also, the properties (weight balance, squirt, strength, stiffness) might be more likely to be more consistent from one shaft to another of the same model.

Regards,
Dave

 

[dr_dave]

A straight maple shaft is stiffer in one direction due to the grain of the wood. The 8 piece pie lamination eliminates the grain factor.

However, stiffness does not affect squirt the way some people might think. For more info, with lots of supporting resources, see:

http://billiards.colostate.edu/threads/squirt.html#endmass​

Although, stiffness differences can affect the "hit" or "feel" of the cue.

Regards,
Dave

 

[Patrick Johnson]

GetMeThere:
Now I realize that probably the easiest thing to do (at least for one variable) is MEASURE speed (of whatever), and ignore tests outside the speed range you consider useful for the test. (i.e., instead of trying to produce perfect MACHINERY, one can choose to collect only perfect "data" from imperfect machinery)

Yes, that's how I design "homebrew" tests. For instance, my test comparing spin produced by various shafts specifies that shots should be discarded if they don't hit the right initial target, don't go the correct distance or don't put a chalk mark in the right place (all to within reasonably tight tolerances).

pj <- no difference found to date
chgo

 

[cheapcues.com]

You are correct; although, some people can play better with low-squirt (AKA low cue-ball deflection, or LD) shafts. There are numerous advantages and disadvantages of LD shafts for different people. FYI, many of them are listed along with supporting rsources here:

http://billiards.colostate.edu/threads/cue.html#low_squirt​

FYI, some data can be found here:

http://billiards.colostate.edu/threads/squirt.html#data​

The data from Platinum Billiards (Predator) is a little suspect, but it is the only large set of data out there.

FYI, if you want to compare cues, it is very easy to test them yourself. You don't need a robot. See the procedure here:

http://billiards.colostate.edu/threads/cue.html#pivot​

Exactly. There are techniques (e.g., BHE and FHE) to account for squirt and swerve to some extents, but swerve varies with distance, speed, cue elevation, amount and type of English, and ball and cloth conditions. Also, throw varies with angle, speed, Engligh amount and type, and ball conditions.

This is a very subjective and personal thing. For more info, see:

http://billiards.colostate.edu/threads/cue.html#feel​

That's why others and I prefer the term "squirt." For more info, see:

http://billiards.colostate.edu/threads/cue.html#terminology​

... not true; although, the shape of the tip can have an effect. For more info, see:

http://billiards.colostate.edu/threads/cue_tip.html#size​

Regards,
Dave

Dr. Dave thank you for your responses and your links. I just watched the video on backhand english and pivot points. That may have been best 5-minute lesson I've ever had!

With regards to tip size and tip shape; in my experience I have always had better success pocketing balls on straight in or nearly straight in shots wil thicker shafts, especially when the CB is against the rail forcing me to hit high on the CB. I am wondering if this may be due to the fact that on smaller shafts there seems to be more room for "play" within my bridge. This may be what is causing me to miss more shots. Also perhaps on smaller tip diameter shafts the tips are usually shaped to a smaller radius so as to "match up" with the shaft diameter. i.e. do 13mm shats usually have a nickel radius and 11.75mm shafts have a dime radius? I'll have to look into that. When I sat down to sketch out why I thought smaller diameter shafts would cause shooting errors I realized that what you said makes sense- the smaller radius of the TIP is what matters, not the diameter of the SHAFT. I think I'll experiment with smaller shafts that have flatter tips, and thicker shafts that have rounder tips just for fun.

I have enjoyed reading your posts on this thread and clearly you have done your homework on this subject, so thank you for contributing to the thread.

 

[dr_dave]

Dr. Dave thank you for your responses and your links. I just watched the video on backhand english and pivot points. That may have been best 5-minute lesson I've ever had!

I'm glad you liked it, and thank you for the kind feedback.

With regards to tip size and tip shape; in my experience I have always had better success pocketing balls on straight in or nearly straight in shots wil thicker shafts, especially when the CB is against the rail forcing me to hit high on the CB. I am wondering if this may be due to the fact that on smaller shafts there seems to be more room for "play" within my bridge. This may be what is causing me to miss more shots.

Sounds reasonable to me.

Also perhaps on smaller tip diameter shafts the tips are usually shaped to a smaller radius so as to "match up" with the shaft diameter. i.e. do 13mm shats usually have a nickel radius and 11.75mm shafts have a dime radius? I'll have to look into that.

This depends only on what shaping tool is used. However, maybe there is a tendency to use a rounder shape on a smaller-diameter tip.

I have enjoyed reading your posts on this thread and clearly you have done your homework on this subject, so thank you for contributing to the thread.

Thanks again ... and you're welcome.

I aim to squerve,
Dave

 

[cheapcues.com]

However, stiffness does not affect squirt the way some people might think. For more info, with lots of supporting resources, see:

http://billiards.colostate.edu/threads/squirt.html#endmass​

Although, stiffness differences can affect the "hit" or "feel" of the cue.

Regards,
Dave

I would not expect stiffness to effect squirt. I would expect it to effect spin rates, and thus swerve and throw. Do you have any info on this? I think swerve and throw are factors that are not addressed nearly as much as squirt and are actually larger issues under most side english shot conditions. When I talk about missing shots when the CB is on the rail those shots are missed because of unwanted swerve, not squirt.

 

[dr_dave]

I would not expect stiffness to effect squirt. I would expect it to effect spin rates, and thus swerve and throw. Do you have any info on this?

Cues do not have enough transverse stiffness to provide significant sideways force during the incredibly brief tip contact time with the CB. Most of the cue's deflection occurs well after the CB is gone. Stiffness doesn't have an effect unless there is enough deflection to create significant force. In other words, stiffness differences should have no practical affect on English. Sorry, but I don't have anything more that addresses this topic directly.

I think swerve and throw are factors that are not addressed nearly as much as squirt and are actually larger issues under most side english shot conditions. When I talk about missing shots when the CB is on the rail those shots are missed because of unwanted swerve, not squirt.

Agreed. Squirt is easy to compensate for, but most English shots are probably missed due to improper swerve compensation (and some due to throw). FYI, I have many resources (from me and others) dealing with these topics here:

http://billiards.colostate.edu/threads/aiming.html#compensation
http://billiards.colostate.edu/threads/aiming.html#English_effects​

Regards,
Dave

 

[vincentwu817]

patrick, that fish looks delicious on your profile picture

 

[vincentwu817]

I'm glad that someone has addressed the issue of swerve and that it is probably more difficult to compensate for than squirt. I think this is especially true a lot of rail cut shots where you use low side spin to control the angle of the cue ball after it touches the rail. The squirt factor isn't so big on these kind of shots.

I'm sure to a certain extent that LD shafts will help people improve their games by minimizing squirt, but I believe that many people too often blame their misses on squirt, instead of swerve and throw.

 

[KMRUNOUT]

I do find it quite amazing how some very good pool pro's use the ''LD'' Shafts. I know they are getting paid to use the products etc but it still amazes me how there are hardly any pro's now a days (or atleast outnumber very highly) use regular maple shafts.

Work on your stroke and other fundamentals, trust them, and play good!

Hard to tell which point you are making here. You're saying that the majority of pros use LD shafts, but you think its better not to? It sounds like your point is that the logic of the pros defies your understanding? What conclusion should one draw here? I'm pretty sure the majority of pros are fundamentally sound, trust their fundamentals, and play good...

KMRUNOUT

 

[iusedtoberich]

It's known and understood that reducing mass near the tip reduces deflection. There's NO KNOWN REASON why merely laminating shafts (Meucci black dot) should make them deflect so much less than "hollow" LD shafts.

When an unexpected (even contrary) result arises, one needs to give some consideration to the experimental setup. I agree that SOMETHING must be wrong with Meucci's experiments--knowing exactly what that is would be useful (for me--because I would sometime like to do some similar things).

The Meucci shaft over the years has had features to reduce the endmass:

1. The ferrule has always been thin walled relative to most other cues. (the plastics used in ferrules is usually of higher density than maple)
2. The ferrule has been made of a less dense material than most other ferrules on competing cues.
3. On recent shafts (black dot), the tenon has been tapered like the end of a pencil (not that extreme), yet the internal walls of the ferrule have remained cylindrical. This further reduces endmass by introducing a tapered hollow region right behind the tip.

This comes from my personal experience replacing ferrules on Meucci shafts. I did not replace many, maybe 10 total over the years.

While Meucci doen't seem to advertise these features, they are what makes their shafts lower deflection than most common shafts.

Interesting side note: 10 years ago, if you asked predator users why their shaft deflected less, they would say "because its laminated". Every picture on Predator's advertisement showed this, and people thought that must be the reason they deflected the cue ball less. The Predator shaft was the first on the market with radial laminations that was widely successful as far as sales go. It was the one thing players could easily see was different on the shaft compared to standard shafts.

Even when Predator included the x-sectoin of the hollowed area in their advertisements, their illustration looked like some sort of rod was inserted into the end of the shaft. It did not look hollow.

Of course, I'm talking about the average pool player, that has no idea what endmass is. I recall even having discussions with players that the radial laminations had nothing to do with why the shaft deflected less, and they wouldn't believe me.

 

[iusedtoberich]

FYI, if you want to compare cues, it is very easy to test them yourself. You don't need a robot. See the procedure here:

http://billiards.colostate.edu/threads/cue.html#pivot​

Regards,
Dave

Dr. Dave,
You need pool glasses. I can tell from this video. Your speed will go up one ball if you get them. Best thing I ever did for my game.

 

[iusedtoberich]

How can 8-pieces of differing laminates have more radial consistency ?
....

1. Do you believe a piece of solid wood is more consistent than a piece of plywood?

2. Do you believe a piece of solid wood is more consistent than Medium Density Fiberboard (MDF)?

3. If you went to the lumbar yard, and wieghed 10 samples of the same sized piece of solid wood (same species), and then weigheed 10 pieces of plywood, which of the two do you beleive would be more consistant in weight from piece to piece?

4. If you made 10 joists with a single 2x12 solid wood beam, and also made 10 joists with 4 pieces of 1/2 inch thick solid wood glued together.... and then measured how much force is required to break each joist, which joists do you think would be most consistent from sample to sample?

 

[iusedtoberich]

Yes, that's how I design "homebrew" tests. For instance, my test comparing spin produced by various shafts specifies that shots should be discarded if they don't hit the right initial target, don't go the correct distance or don't put a chalk mark in the right place (all to within reasonably tight tolerances).

pj <- no difference found to date
chgo

I participated in this experiment. I just want to use this opportunity to verify that no matter if you use:

phenolic
sniper
moori
lepro
jump cue
house cue
break cue

...that if you hit the cueball in the same place, and the cueball travels along the same initial path, and the cueball travels the same distance, the spin will be exactly the same.