Theory of low deflection cues

riedmich

.. dogs' friend ..
Silver Member
Hello,

in this forum I am a new member. Before I have been in a german billards forum for one and a half years. I like playing pool, and not less I am interested in making cue repairs for my friends and fellows of our billard club.

In last times I more and more think about starting to build cues by my own. By experimenting with used butts and shafts I've tried to get a feeling about the direction of the kind of cues that I may build sometime.

A question that I try to understand and where it is impossible to discuss in a gentle and objektive way in that special german forum, is the question about how a low deflection cue "works". What is it that makes a cue producing low deflection.

I read some articles of "Dr. Dave" who is for sure well known for most of american cuemakers. Am I right?

Dr. Daves articles that I read tell, that deflection or "squirt" depends on the so called "endmass" of the cue. The idea of this theory roughly is that especially at the area of the tip and some inches behind at the front end of the shaft the mass or partial weight of the shaft is the factor the decides of having more or less deflection.

I have searched but not found some continuative or alternative theory or meassurements how the stiffness (the flexibility and the bending line) of the shaft's front end or of whole cue stick affects deflection.

I hope that the specialists of this forum can answer this question much better. In my theory the flexibility, especially the way the front end can flex while contacting the white ball is affecting the deflection mostly. In my "opinion" the most important reasons for more or less deflection are both: stiffness of front end and the mass of the front end. Secondly the stiffness of the whole shaft maybe important also. May be it is the relation between static stiffness (or static bending line under a certain applied load that erases while contacting the white ball) and the end mass. The higher the end mass, the higher deflection. The stiffer the front end and the less flexible he front end, the higher the deflection. The stiffer the whole shaft, the higher the deflection. Roughly spoken. This would also explain that the butt and joint also affects deflection, but less as the shaft itself.

I would be very thankful for getting some feasible explanations from the experts of this forum.

With my best wishes
Michael
 
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qbilder

slower than snails
Silver Member
Simply, take the weight of the ball vs. the energy required to deflect the tip end of the cue. The lighter weight the tip end of the cue, the easier it is for it to flex away upon impact. The more it flexes away, the less the ball is pushed off intended track. The heavier it is, the more energy is needed to deflect it so instead, the ball deflects away from the tip, off of intended track. Hopefully that makes sense.
 

qguy

AzB Silver Member
Silver Member
does it mean that a LD shaft will impart more spin given the same amount of deflection vs a conventional shaft ?
 

qbilder

slower than snails
Silver Member
i would think it would be reversed,but i'm not a cue maker..lol.

I probably didn't explain it clearly. It's easy to show but I have a tough time explaining it.

The heavier the tip end of the shaft, the more the ball is deflected away from the tip. The lighter the tip end, the more the tip is deflected away from the ball. It's simple collision physics. The more massive object moves less than the less massive object. A bicycle hits a parked car at 20mph & flips over it or bounces off of it while the car never moves an inch. A car hits a bicycle at 20mph & the car barely slows down while the bicycle rockets away.
 

BHQ

we'll miss you
Silver Member
I probably didn't explain it clearly. It's easy to show but I have a tough time explaining it.

The heavier the tip end of the shaft, the more the ball is deflected away from the tip. The lighter the tip end, the more the tip is deflected away from the ball. It's simple collision physics. The more massive object moves less than the less massive object. QUOTE]


A bicycle hits a parked car at 20mph & flips over it or bounces off of it while the car never moves an inch. A car hits a bicycle at 20mph & the car barely slows down while the bicycle rockets away.

predator should put this on thier website :thumbup:
plain english gets a thumbs up from me anyday over bs & hype
good seeing you at the sbe eric
brenster> concerned about person on the bike in either scenario :thud:
 
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qbilder

slower than snails
Silver Member
does it mean that a LD shaft will impart more spin given the same amount of deflection vs a conventional shaft ?

No. Spin is another demon all together. Spin can certainly cloud the results of deflection but isn't actually related.
 

riedmich

.. dogs' friend ..
Silver Member
... The lighter weight the tip end of the cue, the easier it is for it to flex away upon impact. The more it flexes away, the less the ball is pushed off intended track. The heavier it is, the more energy is needed to deflect it so instead, the ball deflects away from the tip, off of intended track. Hopefully that makes sense ...

So it might be understood also, that not only the weight of the tip end influences the deflection, but also the possibility to flex --> the stiffness?
 

qbilder

slower than snails
Silver Member
So it might be understood also, that not only the weight of the tip end influences the deflection, but also the possibility to flex --> the stiffness?

No. Only mass vs. mass. The most significant mass moves the least amount, regardless of rigidity. You can bridge the shaft very tightly, forcefully not allowing it to move. But in that situation the shaft is assuming your hand's mass because of the tight grip. That in turn negates any low deflection properties the shaft may have.
 

riedmich

.. dogs' friend ..
Silver Member
No. Only mass vs. mass. The most significant mass moves the least amount, regardless of rigidity. You can bridge the shaft very tightly, forcefully not allowing it to move. But in that situation the shaft is assuming your hand's mass because of the tight grip. That in turn negates any low deflection properties the shaft may have.

Talking about the open bridge (edit: shaft not tightly bridged): Is it a difference concerning deflection, if the distance of the bridge to the white ball is very small or if it is very high? Very small distance of bridge - higher deflection?
 
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qbilder

slower than snails
Silver Member
Talking about the open bridge (edit: shaft not tightly bridged): Is it a difference concerning deflection, if the distance of the bridge to the white ball is very small or if it is very high? Very small distance of bridge - higher deflection?

No difference. Nothing measurable, anyway.
 

qbilder

slower than snails
Silver Member
I probably didn't explain it clearly. It's easy to show but I have a tough time explaining it.

The heavier the tip end of the shaft, the more the ball is deflected away from the tip. The lighter the tip end, the more the tip is deflected away from the ball. It's simple collision physics. The more massive object moves less than the less massive object. QUOTE]


A bicycle hits a parked car at 20mph & flips over it or bounces off of it while the car never moves an inch. A car hits a bicycle at 20mph & the car barely slows down while the bicycle rockets away.

predator should put this on thier website :thumbup:
plain english gets a thumbs up from me anyday over bs & hype
good seeing you at the sbe eric
brenster> concerned about person on the bike in either scenario :thud:

That show is a blast. Hundreds of adults acting like college kids.
 

GrimmCustomCues

AzB Silver Member
Silver Member
I probably didn't explain it clearly. It's easy to show but I have a tough time explaining it.

The heavier the tip end of the shaft, the more the ball is deflected away from the tip. The lighter the tip end, the more the tip is deflected away from the ball. It's simple collision physics. The more massive object moves less than the less massive object. A bicycle hits a parked car at 20mph & flips over it or bounces off of it while the car never moves an inch. A car hits a bicycle at 20mph & the car barely slows down while the bicycle rockets away.

I think the car/bicycle comparison is by far the best and simplest cue deflection analogy I've ever heard. Thanks!

Richard
 

greyghost

Coast to Coast
Silver Member
The stiffer the front end and the less flexible he front end, the higher the deflection. The stiffer the whole shaft, the higher the deflection THIS IS WRONG

Deflection is only partially related to stiffness/spine. If a shaft had a stiffer taper that was also thicker then it would have more endmass due to the increase in diameter.

This is much better relayed.

Deflection is caused/effected by the endmass of the cue........endmass can be affected by the taper used on the cue, so if the desired spine/stiffness calls for a taper that changes the mass of the shaft then by association can change the deflection..........association only as it can never be the direct cause, as Eric stated the END MASS IS THE REAL REASON FOR DEFLECTION of the CB on off center hits.


Now Spine or shaft stiffness can and does affect the quantity of CB spin you can attain and to what degrees you can attain said spin on a given speed of shot.
 

riedmich

.. dogs' friend ..
Silver Member
The stiffer the front end and the less flexible he front end, the higher the deflection. The stiffer the whole shaft, the higher the deflection THIS IS WRONG

Deflection is only partially related to stiffness/spine. If a shaft had a stiffer taper that was also thicker then it would have more endmass due to the increase in diameter.

This is much better relayed.

Deflection is caused/effected by the endmass of the cue........endmass can be affected by the taper used on the cue, so if the desired spine/stiffness calls for a taper that changes the mass of the shaft then by association can change the deflection..........association only as it can never be the direct cause, as Eric stated the END MASS IS THE REAL REASON FOR DEFLECTION of the CB on off center hits.


Now Spine or shaft stiffness can and does affect the quantity of CB spin you can attain and to what degrees you can attain said spin on a given speed of shot.

I don't know the mental states of the authorities in this forum, but by no means I would annoy anyone mentioning meucci, and if I do now please excuse me.

I found at meuccis homepage a document about the red dot shaft. http://www.meuccicues.com/reddot.htm It is written that with such flat laminated shafts the radial direction affects the deflection. If this is true this could mean that shaft-stiffness influences deflection as well as its mass/weight. Does this document tell the truth? Or is it a special matter of advertisement by meucci?

May be there are some persons knowing about these flat laminated shafts like red dot.

Thanks a lot
Michael
 

JoeyInCali

Maker of Joey Bautista Cues
Silver Member
I don't know the mental states of the authorities in this forum, but by no means I would annoy anyone mentioning meucci, and if I do now please excuse me.

I found at meuccis homepage a document about the red dot shaft. http://www.meuccicues.com/reddot.htm It is written that with such flat laminated shafts the radial direction affects the deflection. If this is true this could mean that shaft-stiffness influences deflection as well as its mass/weight. Does this document tell the truth? Or is it a special matter of advertisement by meucci?

May be there are some persons knowing about these flat laminated shafts like red dot.

Thanks a lot
Michael

Red Dot is not a plywood.
Black Dot is.
That is an ad . Take it like a best tasting beer ad.
 

riedmich

.. dogs' friend ..
Silver Member
Oh, sorry. I thought red dot is similar to black dot.

But what about the mentioned affect on deflection by different radial position? Is this a true affect, or it is advertising?
 

cigardave

Who's got a light?
Silver Member
I think the car/bicycle comparison is by far the best and simplest cue deflection analogy I've ever heard. Thanks!

Richard
But that analogy does not address end mass... just total mass... fwiw.

It's the end mass aspect that is difficult to intuitively understand.
 

RBC

Deceased
You can't say that shaft stiffness has no role in cue ball deflection, but it really is a very small amount.

What you have to keep in mind is that all the energy that creates cue ball squirt or deflection transfers from the cue to the ball during contact. That contact only lasts a fraction of a second and during that time, the shaft can't really flex all that much regardless of how stiff it is. So, even though one shaft may be much stiffer than another, it may have much less cue ball squirt or deflection.

The bridge argument is the same thing. The cue ball is long gone from the cue tip by the time the hand can flex and cause a change to the shaft stiffness. Therefore, the type and rigidness of your bridge would have a very hard time changing the cue ball squirt or deflection.

It really does come down to effective tip end mass, and that almost entirely comes from the mass of materials used in construction and their integrity.

I hope this helps
 

JoeyInCali

Maker of Joey Bautista Cues
Silver Member
You can't say that shaft stiffness has no role in cue ball deflection, but it really is a very small amount.

What you have to keep in mind is that all the energy that creates cue ball squirt or deflection transfers from the cue to the ball during contact. That contact only lasts a fraction of a second and during that time, the shaft can't really flex all that much regardless of how stiff it is. So, even though one shaft may be much stiffer than another, it may have much less cue ball squirt or deflection.

The bridge argument is the same thing. The cue ball is long gone from the cue tip by the time the hand can flex and cause a change to the shaft stiffness. Therefore, the type and rigidness of your bridge would have a very hard time changing the cue ball squirt or deflection.

It really does come down to effective tip end mass, and that almost entirely comes from the mass of materials used in construction and their integrity.

I hope this helps
tap tap tap
What's the weight of your ferrule by cubic cm, RB ?
 
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