One More Shaft Deflection Question

1 Pocket Ghost

1 Pocket Ghost

AzB Silver Member
Silver Member
I have a shaft deflection question that I don't believe was ever put forth/covered in any of the other shaft deflection, ld shafts, squirt, etc. threads...I'm aware of the fact that that weight at the end of the shaft increases deflection, but my question here, pertains to the entire shaft...maybe the science guys, or cuebuilders can give me an answer...

Ok, I have two cues (and by the way, this is a real situation - not hypothetical)...both of these cues,,,

Weigh the same - 19.oz

Have the same balance point @ 19"

Have the same joint screw and same phenolic joint sleeves

Have standard hard rock maple shafts made by a custom cuemaker

Both shafts have a similar modified pro taper, are 13mm and have the same ferrule type and length, and the same type of tip

The one difference in the specs of the cues is...that although they both weigh 19oz., Cue A has a butt that weighs 14.8 with a shaft that weighs 4.2...while Cue B has a butt that weighs 15.2 with a shaft that weighs 3.8...

All of that said...My situation is: Cue A when shot with, produces decidedly more deflection and squirt than Cue B does...

So my question is: Is the significantly higher amount of deflection produced by Cue A happening because of it's heavier shaft?...:confused:

Thanks for all replies, Ghost
 
The answer to your question Ghost, is yes, but there's a ton of science behind that affirmation. Check out Dr. Dave's web site and you'll find all the information you need on squirt, swerve, and squerve. One Pocket rules.
 
Ghostie:
Bob Jewett and possibly Dr. Dave are the ones to really answer this. But from what I can gather from the science palather is that the deflection characteristics that you are concerned with are effected by the mass of the shaft at the tip end. Lower mass at the tip end roughly translates into lower deflection.

That's why it seems both Predator and OB do some sort of modifications at the tip end of their low deflection shafts such as hollowing out the wood and replacing it with either foam or a lower density wood.

Dr. Demonrho

1 Pocket Ghost said:
I have a shaft deflection question that I don't believe was ever put forth/covered in any of the other shaft deflection, ld shafts, squirt, etc. threads...I'm aware of the fact that that weight at the end of the shaft increases deflection, but my question here, pertains to the entire shaft...maybe the science guys, or cuebuilders can give me an answer...

Ok, I have two cues (and by the way, this is a real situation - not hypothetical)...both of these cues,,,

Weigh the same - 19.oz

Have the same balance point @ 19"

Have the same joint screw and same phenolic joint sleeves

Have standard hard rock maple shafts made by a custom cuemaker

Both shafts have a similar modified pro taper, are 13mm and have the same ferrule type and length, and the same type of tip

The one difference in the specs of the cues is...that although they both weigh 19oz., Cue A has a butt that weighs 14.8 with a shaft that weighs 4.2...while Cue B has a butt that weighs 15.2 with a shaft that weighs 3.8...

All of that said...My situation is: Cue A when shot with, produces decidedly more deflection and squirt than Cue B does...

So my question is: Is the significantly higher amount of deflection produced by Cue A happening because of it's heavier shaft?...:confused:

Thanks for all replies, Ghost
Click to expand...
 
Last edited:
1 Pocket Ghost said:
I have a shaft deflection question that I don't believe was ever put forth/covered in any of the other shaft deflection, ld shafts, squirt, etc. threads...I'm aware of the fact that that weight at the end of the shaft increases deflection, but my question here, pertains to the entire shaft...maybe the science guys, or cuebuilders can give me an answer...

Ok, I have two cues (and by the way, this is a real situation - not hypothetical)...both of these cues,,,

Weigh the same - 19.oz

Have the same balance point @ 19"

Have the same joint screw and same phenolic joint sleeves

Have standard hard rock maple shafts made by a custom cuemaker

Both shafts have a similar modified pro taper, are 13mm and have the same ferrule type and length, and the same type of tip

The one difference in the specs of the cues is...that although they both weigh 19oz., Cue A has a butt that weighs 14.8 with a shaft that weighs 4.2...while Cue B has a butt that weighs 15.2 with a shaft that weighs 3.8...

All of that said...My situation is: Cue A when shot with, produces decidedly more deflection and squirt than Cue B does...

So my question is: Is the significantly higher amount of deflection produced by Cue A happening because of it's heavier shaft?...:confused:

Thanks for all replies, Ghost
Click to expand...



Are both cues made by the same cue maker?
 
1 Pocket Ghost said:
I have a shaft deflection question that I don't believe was ever put forth/covered in any of the other shaft deflection, ld shafts, squirt, etc. threads...I'm aware of the fact that that weight at the end of the shaft increases deflection, but my question here, pertains to the entire shaft...maybe the science guys, or cuebuilders can give me an answer...

Ok, I have two cues (and by the way, this is a real situation - not hypothetical)...both of these cues,,,

Weigh the same - 19.oz

Have the same balance point @ 19"

Have the same joint screw and same phenolic joint sleeves

Have standard hard rock maple shafts made by a custom cuemaker

Both shafts have a similar modified pro taper, are 13mm and have the same ferrule type and length, and the same type of tip

The one difference in the specs of the cues is...that although they both weigh 19oz., Cue A has a butt that weighs 14.8 with a shaft that weighs 4.2...while Cue B has a butt that weighs 15.2 with a shaft that weighs 3.8...

All of that said...My situation is: Cue A when shot with, produces decidedly more deflection and squirt than Cue B does...

So my question is: Is the significantly higher amount of deflection produced by Cue A happening because of it's heavier shaft?...:confused:

Thanks for all replies, Ghost
Click to expand...

if thats the only variable changed in the equation, then its obvious that that should be the reason b/h the change. Without going into einstein theorys and such lol. What made ya ask anyways brother?
 
demonrho said:
Ghostie:
Bob Jewett and possibly Dr. Dave are the ones to really answer this. But from what I can gather from the science palather is that the deflection characteristics that you are concerned with are effected by the mass of the shaft at the tip end. Lower mass at the tip end roughly translates into lower deflection.

That's why it seems both Predator and OB do some sort of modifications at the tip end of their low deflection shafts such as hollowing out the wood and replacing it with either foam or a lower density wood.

Dr. Demonrho
Click to expand...


No Don....I made the point in the beginning of my post that I'm already aware of all of the info re. the effects of weight/mass at the tip end of the shaft....this is a different situation, as both of these aforementioned cues/shafts are structured the same at the tip end.

- Ghost
 
greyghost said:
if thats the only variable changed in the equation, then its obvious that that should be the reason b/h the change. Without going into einstein theorys and such lol. What made ya ask anyways brother?
Click to expand...


There is one other variable - butt wood...the cue with the heavier butt is made of African Blackwood - the cue with the lighter butt is made of primarily curly Maple...I don't know if this could play into it...:confused:

- Ghost
 
1 Pocket Ghost said:
No, they are not.
Click to expand...

Then I would suggest that the major difference between them is the over all taper of the cue. A cues taper can have a major effect on a cues overall deflection, I learned list as I learned this while I was learning to build cues.

In most cases each cue maker has developed their own taper that is used on their shafts and the butts. Today, many use the Parabolic Taper that was invented by David Kershinbrock, and that is also used by Southwest, Bender, along with many others. This taper is designed to transmit power / energy without negative feedback.

JIMO
 
1 Pocket Ghost said:
....this is a different situation, as both of these aforementioned cues/shafts are structured the same at the tip end...

- Ghost
Click to expand...

Both shafts have the exact same density mass ratio per volume throughout their length? Oh, sorry, yes, you must have used m=\int_V\rho(\vec(r)dV.
 
If you absolutely need the answer---here's the solution.

Take both shafts and saw off the last 8 inches at the tip. Now weight each piece and compare. Presto---you are now knowledgeable.
 
1 Pocket Ghost said:
No Don....I made the point in the beginning of my post that I'm already aware of all of the info re. the effects of weight/mass at the tip end of the shaft....this is a different situation, as both of these aforementioned cues/shafts are structured the same at the tip end.

- Ghost
Click to expand...

If you're aware of what influences squirt, and you're saying that all things are equal except one shaft weighs 10% more than the other, then what do you think is the difference in the first several inches of the shafts? Weight.

And even the people who try to explain what causes squirt don't get it right. They keep dropping the word "effective" which is the crux of it.

There are three or four things that determine squirt: Contact time, lateral wave propogation rate, density of the material within the length of wave propogation during contact.

The total mass within the length of wave propogation during contact is the total mass in lateral effect during the contact time with the cueball or "effective tip end mass." For some reason, people just say "tip end mass" which misses way too much.

Anyway, anything that affects any of these three will affect squirt. In your case, it looks like you have a higher density in that effective length. In fact, I now will start using a new term: effective tip end length.

Now, I'm sure this will be another term and explanation that will be credited to someone else.

Fred <~~~ explained the sideways wave propogation over 10 years ago
 
1 Pocket Ghost said:
There is one other variable - butt wood...the cue with the heavier butt is made of African Blackwood - the cue with the lighter butt is made of primarily curly Maple...I don't know if this could play into it...:confused:

- Ghost
Click to expand...

yes it definately can, remember the nodal points of a cue affect its play. The farther out to the ends of the cue the nodal points are the stiffer its going to play. The denser wood also is going to change the vibration through out the cue and how that energy is used and transferred. Just as tone of the wood influences playability, a denser wood will generally have a higher tone than a less dense one. A great way to test this would be to have two cues like you described built but will the exact same materials/types of wood. Tapers should always be the same through out the cue also when trying to see what affects what.
 
1 Pocket Ghost said:
I have a shaft deflection question that I don't believe was ever put forth/covered in any of the other shaft deflection, ld shafts, squirt, etc. threads...I'm aware of the fact that that weight at the end of the shaft increases deflection, but my question here, pertains to the entire shaft...maybe the science guys, or cuebuilders can give me an answer...

Ok, I have two cues (and by the way, this is a real situation - not hypothetical)...both of these cues,,,

Weigh the same - 19.oz

Have the same balance point @ 19"

Have the same joint screw and same phenolic joint sleeves

Have standard hard rock maple shafts made by a custom cuemaker

Both shafts have a similar modified pro taper, are 13mm and have the same ferrule type and length, and the same type of tip

The one difference in the specs of the cues is...that although they both weigh 19oz., Cue A has a butt that weighs 14.8 with a shaft that weighs 4.2...while Cue B has a butt that weighs 15.2 with a shaft that weighs 3.8...

All of that said...My situation is: Cue A when shot with, produces decidedly more deflection and squirt than Cue B does...

So my question is: Is the significantly higher amount of deflection produced by Cue A happening because of it's heavier shaft?...:confused:

Thanks for all replies, Ghost
Click to expand...




A qualification re. the similarity of the shaft tapers >>>

Both shafts have tapered up, starting at the ferrule end, a little more then 2,000ths to the inch - both having gone up to 35,000ths at the 15" mark.


- Ghost
 
Excellent answer Fred. For squirt (AKA cue ball deflection), all that matters is the "effective endmass." For people who want more info, I have lots of info (including articles, videos, and analysis) on this topic here:


Regards,
Dave

Cornerman said:
If you're aware of what influences squirt, and you're saying that all things are equal except one shaft weighs 10% more than the other, then what do you think is the difference in the first several inches of the shafts? Weight.

And even the people who try to explain what causes squirt don't get it right. They keep dropping the word "effective" which is the crux of it.

There are three or four things that determine squirt: Contact time, lateral wave propogation rate, density of the material within the length of wave propogation during contact.

The total mass within the length of wave propogation during contact is the total mass in lateral effect during the contact time with the cueball or "effective tip end mass." For some reason, people just say "tip end mass" which misses way too much.

Anyway, anything that affects any of these three will affect squirt. In your case, it looks like you have a higher density in that effective length. In fact, I now will start using a new term: effective tip end length.

Now, I'm sure this will be another term and explanation that will be credited to someone else.

Fred <~~~ explained the sideways wave propogation over 10 years ago
Click to expand...
 
1 Pocket Ghost said:
,snip>
So my question is: Is the significantly higher amount of deflection produced by Cue A happening because of it's heavier shaft?...:confused:
Click to expand...

As Dr Dave indicates, deflection is all about where the mass is. If the tip-end mass is light the cure will have low deflection. One could theoretically add lead/tungsten to the joint end of the shaft to make it heavier, and it would not alter the delfection characteristics whatsoever.

Its not the amount of mass, it is where the mass is.
 
MitchAlsup said:
As Dr Dave indicates, deflection is all about where the mass is. If the tip-end mass is light the cure will have low deflection. One could theoretically add lead/tungsten to the joint end of the shaft to make it heavier, and it would not alter the delfection characteristics whatsoever.

Its not the amount of mass, it is where the mass is.
Click to expand...
... and as Fred pointed out, the stiffness of the end of the shaft can also have an effect (but not like some people might think). For example, a carbon-fiber shaft, which can be much lighter and stiffer than wood, can have more squirt. What's important is the "effective endmass" (which is mostly due to the mass of the last 4-6 inches of the shaft, but stiffness can play a role also). For more info, see:


Regards,
Dave
 
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