Flex Point Question

HawaiianEye

AzB Silver Member
Silver Member
Every cue has a flex point on the shaft.

On a pro taper, I would assume the flex point would be where the straight taper of the shaft stopped and where the taper starts increasing going towards the joint.

Is this correct?

If not, what determines the flex point? Is it the smallest diameter of the shaft between the tip and the joint?

The reason I'm asking is that if a player knew the flex point on a shaft they liked, they could order a certain flex point on a shaft when it was being turned.
 

JoeyInCali

Maker of Joey Bautista Cues
Silver Member
Every cue has a flex point on the shaft.

On a pro taper, I would assume the flex point would be where the straight taper of the shaft stopped and where the taper starts increasing going towards the joint.

Is this correct?

If not, what determines the flex point? Is it the smallest diameter of the shaft between the tip and the joint?

The reason I'm asking is that if a player knew the flex point on a shaft they liked, they could order a certain flex point on a shaft when it was being turned.
The smallest diameter between the tip and the joint is the tip. :D
I have yet to hear about a player knowing the flex point of his shafts.
Pivot point, maybe.
Cue makers test how flexible or stiff their shafts by simple gripping both end pushing the shaft with the two thumbs.
You do that enough, you get to feel how stiff the shafts are .
And you can see where the shaft bends.
The closer to the joint the flex is, the whippier it gets.
 

Chopdoc

AzB Silver Member
Silver Member
This is an interesting notion. I wonder what other makers think of it.

Shaft flex point as a specification?


The reason I'm asking is that if a player knew the flex point on a shaft they liked, they could order a certain flex point on a shaft when it was being turned.

Even a stiff shaft has a flex point. Stiffness would seem to be independent of flex point. Both could be measured and quantified.

In this day of high tech shafts it might be interesting to some see cue makers quantify some of these things for their shafts.


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johnnysd

AzB Silver Member
Silver Member
It is interesting that I don't think enough attention is paid to the characteristics of a shaft other than "deflection". It would be interesting to know the flex point and pivot point and stiffness and how that relates to the overall taper of the shaft.
 

HawaiianEye

AzB Silver Member
Silver Member
Cue makers test how flexible or stiff their shafts by simple gripping both end pushing the shaft with the two thumbs.
You do that enough, you get to feel how stiff the shafts are .
And you can see where the shaft bends.
The closer to the joint the flex is, the whippier it gets.

OK.

Assuming you are using the same supply of shaft wood, turned to the same dimensions, are the flex points different between shafts?

If so, how far apart.

If you make a 13mm shaft with your current taper, how far down the shaft is the flex point?

And why is it at that point? Is it because the taper changed or is it due to the characteristics of the wood?
 

PoppaSaun

Banned
The shaft doesn't have a flex point. Every shaft will bend some over the entire length. There is a point in which the rate of bend will be the highest, but it all depends on how the forces are applied.

Joey describes moment-loading of both ends.

The way a cue is used is much closer to a cantilevered beam, but the main force calculation is more of a buckling situation.

One might argue that you could look for a certain amount of deflection for a given force applied to the tip, but that will change the taper...which will affect how the cue performs in a buckling situation.

Joey is correct, tho, for a given taper, similar stiffness will likely provide similar results.
 

Chopdoc

AzB Silver Member
Silver Member
The shaft doesn't have a flex point. Every shaft will bend some over the entire length. There is a point in which the rate of bend will be the highest, but it all depends on how the forces are applied.

I believe this is what is being talked about.

Forces applied to the ends of course.




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bdcues

AzB Silver Member
Silver Member
Every cue has a flex point on the shaft.

On a pro taper, I would assume the flex point would be where the straight taper of the shaft stopped and where the taper starts increasing going towards the joint.

Is this correct?

If not, what determines the flex point? Is it the smallest diameter of the shaft between the tip and the joint?

The reason I'm asking is that if a player knew the flex point on a shaft they liked, they could order a certain flex point on a shaft when it was being turned.

Have to assume you mean pivot point and I am not sure that can be measured in any way besides hitting balls. And finding the pivot point simply requires changing the bridge length until you figure it out.

Years ago Meucci did testing for radial consistency, mostly trying to show that his shafts were more radially consistent then laminated shafts and failing, but what his test did show was how stiff any one shaft was. Supposedly Predator is now testing each triangle for stiffness and matching 10 pieces. Problem is that unless there is a numbering system stamped somewhere one would never know if in buying 2 shafts at once they were the same stiffness of not.

As to why cue makes don't go through all this fuss..... time and money. Their time and your money. Even with the same taper, same weight and same stiffness two shafts may not play exactly alike.

As for your first assumption.... no. Assuming no taper rise it does not follow that the pivot point will be at the point where the taper starts to rise. Much would depend on the stiffness of the wood and ferrule diameter. Then you get into the problem of shafts with taper rise.... which is most.

Given that, we could test each shaft for flex stiffness and match them to other shafts of the same weight. It would just cost more money to the buyer. Currently we match weights if someone orders 2 similar shafts or orders a second shaft later. This is standard for us.
 

louieatienza

AzB Silver Member
Silver Member
I think the better term would be bend profile. It's done with golf shafts, and fitters have a program with over 2000 shafts, with measurements for frequency to bend profile to weight to weight distribution, etc... to help match a shaft to the golfer's swing to maximize distance and accuracy. They can affect trajectory (high or low) and direction (draw or fade bias).

General stiffness of a shaft is directly related to it's frequency. This can be standardized by clamping the weight of a cue-ball at the end of a shaft, then clamping the joint end to a fixture, and flick the weighted end to measure the frequency. The ones used for golf shafts are not that expensive and likely would work. I'd predict that given the same dimensions, the two shafts with the closest frequencies would play the most similar.
 

HawaiianEye

AzB Silver Member
Silver Member
I think the better term would be bend profile. It's done with golf shafts, and fitters have a program with over 2000 shafts, with measurements for frequency to bend profile to weight to weight distribution, etc... to help match a shaft to the golfer's swing to maximize distance and accuracy. They can affect trajectory (high or low) and direction (draw or fade bias).

General stiffness of a shaft is directly related to it's frequency. This can be standardized by clamping the weight of a cue-ball at the end of a shaft, then clamping the joint end to a fixture, and flick the weighted end to measure the frequency. The ones used for golf shafts are not that expensive and likely would work. I'd predict that given the same dimensions, the two shafts with the closest frequencies would play the most similar.

That's what I'm talkin' 'bout. :) Something along the lines of that. Being able to figure out and adjust the shaft to your liking.

http://sirshanksalot.com/the-ultimate-golf-shaft-101-guide/

http://golftips.golfweek.com/flex-point-golf-shaft-20118.html

https://www.hirekogolf.com/media/pdf/chapter4.pdf

http://www.golfalot.com/buyingguides/shafts.aspx

What is a shaft kick-point (Flex-point)?

This defines the point where the shaft bends and affects the trajectory of the shot. The effect is small but measurable. A shaft with a high kick-point will usually give a low shot trajectory and more of a "one-piece" feel to the shaft. A low Kick-point will usually give a high shot trajectory and a feeling of the shaft tip whipping the clubhead through.

Kick-point will also affect the feel of the shaft. Some club specialists will dispute this by saying that the Kick-point and bend-point are the same. Bend-point is the highest point of the shaft when it is bending by applying pressure to both ends of the shaft. Kick-point is the highest point the shaft is bending, by clamping down the grip and pressure is applied onto the club head, like in the swing. There will be some shafts where both bending points are similar or very close.
 
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Chopdoc

AzB Silver Member
Silver Member
Have to assume you mean pivot point and I am not sure that can be measured in any way besides hitting balls. And finding the pivot point simply requires changing the bridge length until you figure it out.


I think most of us are familiar with Meucci's studies on the matter. Good history there.

As far as the bridge hand, that is a good observation.

But we also know that the taper profile behind the bridge hand upon contact with the cue ball has something to do with how the shaft plays as well. The bridge hand is not a rigid point, and it moves relative to the end of the cue with the stroke.

The style of the bridge would also have something to do with it I would think, such as open versus closed perhaps as examples of two extremes.

As the OP posted:
The reason I'm asking is that if a player knew the flex point on a shaft they liked, they could order a certain flex point on a shaft when it was being turned.

We order shafts by weight, length, length of taper, profile of taper, and ferrule type. Could this proposed parameter be of some additional value in standardizing a parameter or specification?

I am seeing some interesting input. Terminology and semantics aside, I still am thinking there may be value in it.


Why?

The cue makers are increasingly competing against technologies like Predator, OB, Cuetec, Lucasi...and offerings from US "custom" makers like Jacoby and Joss for example.

Isn't being able to tailor make a cue for a player one of the advantages of ordering a custom cue? I mean it isn't just looks, finish quality, etc.

When a player says he wants a shaft to play exactly like his "X" shaft he usually mentions the specs and then some qualitative terms. The more the qualitative terms can be quantified the better the custom maker can meet the customer's requirements I think.




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bdcues

AzB Silver Member
Silver Member
I think most of us are familiar with Meucci's studies on the matter. Good history there.

As far as the bridge hand, that is a good observation.

But we also know that the taper profile behind the bridge hand upon contact with the cue ball has something to do with how the shaft plays as well. The bridge hand is not a rigid point, and it moves relative to the end of the cue with the stroke.

The style of the bridge would also have something to do with it I would think, such as open versus closed perhaps as examples of two extremes.

As the OP posted:


We order shafts by weight, length, length of taper, profile of taper, and ferrule type. Could this proposed parameter be of some additional value in standardizing a parameter or specification?

I am seeing some interesting input. Terminology and semantics aside, I still am thinking there may be value in it.


Why?

The cue makers are increasingly competing against technologies like Predator, OB, Cuetec, Lucasi...and offerings from US "custom" makers like Jacoby and Joss for example.

Isn't being able to tailor make a cue for a player one of the advantages of ordering a custom cue? I mean it isn't just looks, finish quality, etc.

When a player says he wants a shaft to play exactly like his "X" shaft he usually mentions the specs and then some qualitative terms. The more the qualitative terms can be quantified the better the custom maker can meet the customer's requirements I think.




.

That's all well and good but you are dealing with wood, the properties of which are different from piece to piece. There is also the difference that what your are comparing, golf and pool, differ. I am a great proponent of the value of kick points and in personal discussions about shafts have given my ideas on more than one occasion. But I also know that kick points are not found by pushing on the side of the ferrule.

Secondly, players like different things. The cost to industry, an industry that is a fraction of that of the golf club industry, would be born by whom? Is everyone going to buy a $500 one piece or laminated shaft? Hardly. Look at the new Predator shaft... one taper, one ferrule diameter, one color, one...... And the price? Years of research to make one shaft with no options. Now make it out of wood. Now satisfy the demands of everyone with enough money to buy one per his personal specifications.

As for the bridge hand not being a stable point.... I suggest you stop moving your bridge hand while shooting, your accuracy will improve. :)

HE's comment about adjusting the shaft to ones liking.... cuemakers have been doing this for years, it is called sanding back the taper.
 

Chopdoc

AzB Silver Member
Silver Member
As for the bridge hand not being a stable point.... I suggest you stop moving your bridge hand while shooting, your accuracy will improve. :)


OK...I just sat down to a perfectly mixed Bacardi and Coke...and you made me laugh...Bacardi and Coke hurts like a mother when you laugh it up into your nose! :thumbup::thumbup::thumbup:

I said it's not a rigid point...I didn't say it isn't a stable point...different matter, ideally it is a stable point of course. :wink:


Anyway, I get all that you are saying.

To get what I am saying, please go look into the archer's paradox. :wink:

The human bridge hand is not a rigid point. The apex of what the OP refers to as the "flex point" actually is somewhere behind the bridge hand. I am confident companies like Predator and BeCue are looking at that.

Yes, wood is a less consistent material, but it is graded and selected in grades by cue makers for certain characteristics. And then of course it is tapered to meet certain characteristics.

Could not the characteristic that the OP proposes be quantified and hence offered as a specification by makers of custom "traditional" wood shafts?

I think that is the question at hand.



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bdcues

AzB Silver Member
Silver Member
OK...I just sat down to a perfectly mixed Bacardi and Coke...and you made me laugh...Bacardi and Coke hurts like a mother when you laugh it up into your nose! :thumbup::thumbup::thumbup:

I said it's not a rigid point...I didn't say it isn't a stable point...different matter, ideally it is a stable point of course. :wink:


Anyway, I get all that you are saying.

To get what I am saying, please go look into the archer's paradox. :wink:

The human bridge hand is not a rigid point. The apex of what the OP refers to as the "flex point" actually is somewhere behind the bridge hand. I am confident companies like Predator and BeCue are looking at that.

Yes, wood is a less consistent material, but it is graded and selected in grades by cue makers for certain characteristics. And then of course it is tapered to meet certain characteristics.

Could not the characteristic that the OP proposes be quantified and hence offered as a specification by makers of custom "traditional" wood shafts?

I think that is the question at hand.



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Predator did look into it... and came up with a non wood solution.

Where the flex (kick) point is has no relation to where the hand is. Back hand English will show you this.

Yes, cuemakers grade shafts.... straightness of grain, run-out, gpi, density, color, mineral stain, sugar marks. Now put one of hundreds of tapers currently in use and tell me where the kick point will be. One piece shafts have a range, laminated ld shafts have another. And if you are lucky enough to figure it out for one ferrule diameter and taper go on to the end .25mm smaller shaft and start again

Again, who is going to pay for this? Perhaps you could call Predator and ask them to share their information with you or all of us. What name do you make cues under? Perhaps you have enough clout to get some useful information out of them. One prominent cue maker that posts here at times suggests that a standard joint size might be in the future. Why that would be desirable I have no idea. Just as having only one option for a shaft seems undesirable but by the same token I do not see infinite standardized options in wood shafts being developed unless the price goes infinitely high also.
 

conetip

AzB Silver Member
Silver Member
Bob raises a good point. Even with composites, it is very difficult to get the exact same results. Many carbon fibre products, look the same, weigh the same, but are not the same. Some applications highlight this a lot more than other applications of the technology. In saying that, carbon shafts in their manufacturing process can be tuned quite a bit to ensure they are very close to the same.
Neil
 

Chopdoc

AzB Silver Member
Silver Member
Bob raises a good point. Even with composites, it is very difficult to get the exact same results.


And yet diameters are measured to the fraction of a mm and tapers are precisely cut on a lathe. Why bother? For repeatable results. That's the only reason actually.




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Chopdoc

AzB Silver Member
Silver Member
Predator did look into it... and came up with a non wood solution.

Where the flex (kick) point is has no relation to where the hand is. Back hand English will show you this.

Yes, cuemakers grade shafts.... straightness of grain, run-out, gpi, density, color, mineral stain, sugar marks. Now put one of hundreds of tapers currently in use and tell me where the kick point will be. One piece shafts have a range, laminated ld shafts have another. And if you are lucky enough to figure it out for one ferrule diameter and taper go on to the end .25mm smaller shaft and start again

Again, who is going to pay for this? Perhaps you could call Predator and ask them to share their information with you or all of us.



Well, I guess it has degraded to you being condescending.

Of course it's a range.

And a cue maker need only figure out such points for his own shafts or those he intends to replicate for a customer. Probably take 60 seconds to measure.

Sorry for talking.

It does make one wonder how those archers can get such pin point accuracy out of wood arrows though, since wood is so incredibly inconsistent and its properties vary so much. Must be magic.

I'll let HawaiianEye converse further on the matter if he is interested. :wink:

Hasta la vista! :thumbup:



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ratcues

No yodeling, please.
Silver Member
On a pro taper, I would assume the flex point would be where the straight taper of the shaft stopped and where the taper starts increasing going towards the joint.

I've said this before and I'll say it again. The term "pro taper" is one of the most misused terms I deal with. I refer to it as a compound taper. There are two distinct straight(cones) tapers in a compound taper shaft. The point at which they meet is referred to as the "flex point." Typically, it is measured in inches from the tip towards the joint. A 12 inch taper is stiffer than a 16 inch taper.
 

HawaiianEye

AzB Silver Member
Silver Member
I've said this before and I'll say it again. The term "pro taper" is one of the most misused terms I deal with. I refer to it as a compound taper. There are two distinct straight(cones) tapers in a compound taper shaft. The point at which they meet is referred to as the "flex point." Typically, it is measured in inches from the tip towards the joint. A 12 inch taper is stiffer than a 16 inch taper.

Thank you. That is the kind of information I was hoping someone would provide.
 

bdcues

AzB Silver Member
Silver Member
Well, I guess it has degraded to you being condescending.

Of course it's a range.

And a cue maker need only figure out such points for his own shafts or those he intends to replicate for a customer. Probably take 60 seconds to measure.

Sorry for talking.

It does make one wonder how those archers can get such pin point accuracy out of wood arrows though, since wood is so incredibly inconsistent and its properties vary so much. Must be magic.

I'll let HawaiianEye converse further on the matter if he is interested. :wink:

Hasta la vista! :thumbup:



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If it is condescension to point out that you don't make shafts then my apologies but perhaps you can show the correlation between the arrow and the shaft. Perhaps we should be firing arrows at the cueball?

Thanks Ryan for defining the term. The problem for the OP is that standardizing the resulting playing characteristics so that a buyer could call any cue maker, ask for the "flex point" to be at xx inches and expect the shaft to play the same as every other cue makers shaft with the "flex point" at xx inches will not happen.

There is no hard fast correlation between gpi, density and stiffness. As an example, when processing a group of Maple boards to make my laminated shafts, once they are glued up and turned round they are weighed. They are then divided into as many as 23 different weight classes with a total difference of weight of about 70 grams. Same length, same diameter, 70 grams difference in weight from top to bottom.
 
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