Taper of the butt portion?

PoppaSaun · Feb 16, 2017

This has to be the stupidest conversation ever.

First, there is no such thing as a 'full parabola'. Parabolas are, by definition, infinite. Ipso facto, every parabolic curve is neither complete nor incomplete, for it is complete unto itself, but can never contain every bit of the parabola from which it was taken.

Second, parabolas are widely used for estimating curves of all sorts. This is because given three points on any curve, a parabolic formula can be derived to closely follow curving sections. This model works for curves that have gentle sweeps and don't go from concave to convex. In something like a cue butt or shaft, I expect one could use fewer than three parabolic functions for a model and be within 5% of the actual shape.

All of you geometry dropouts can exit this conversation now, one needs to have at least gotten through differential and integral calculus to further participate.

MVPCues · Feb 16, 2017

cue fix said:
Hello again. It seems as my post has caused some difference issues, which was not my intent. I was curious as to the type of taper was on my cue as I have had several old cues with this taper and as one cue maker mentioned, some people tell you your cue is warped because the joint doesn't touch the surface like most cues. The cues forearm is only 10" from wrap to end of the cue. the wrap is 15" and from the butt sleeve up the wrap for 11" it decreases at .01" per inch, then the last 4" of the wrap it decreases .03" per inch. The cue is an old Martin. I appreciate the insight of those who responded to my post and hope that the differences can be resolved.

No worries. Most of our differences will never be resolved, and we don't really want that to happen 100%. The majority of us are good natured to each other and want to edify in order to further the craft in whatever way we can contribute.

Hopefully we, as a group, didn't fail to answer your question.

Bigb'scues · Feb 16, 2017

The way I read it is he may be talking about those bogus barioni cues

shakes · Feb 17, 2017

tsp&b said:
A Parabola... is a curve formed by the set of points in a plane that are all equally distant from both a given line (called the directrix) and a given point (called the focus) that is not on the line.

qbuilder said:

but only a section taken from one half of a parabola. Or at least that's what I'm trying to articulate.

Then since it is only part or changes that should be called a partial parabola, or perhaps a variable parabolic or compound parabolic taper, Right?

Click to expand...

I believe what you are trying to say is that this isn't a parabolA taper. It is parabolIC. Using your definition snippet :"of, relating to, or resembling a parabola", it doesn't have to be a true ParabolA to be ParabolIC.

Click to expand...

qbilder · Feb 17, 2017

shakes said:
tsp&b said:

"of, relating to, or resembling a parabola", it doesn't have to be a true ParabolA to be ParabolIC.

Click to expand...

Bingo! It's that simple, at least in my mind.

GBCues · Feb 17, 2017

Wow, I go away for a day and look what has happened!
First of all, Todd, I hope you didn't take my post as criticism, it certainly wasn't meant to be.
What I was hoping for was the discussion that resulted.
As to Mr. Shakes, there are several of us here who have backgrounds in math and science. I have a B.S. in Mathematics, I know Kelly (MVPCues) also is well versed in the subject. I don't know the backgrounds of all the others but that doesn't mean they don't have the backgrounds to chime in. But it doesn't require any knowledge of differential equations or the calculus to discuss the geometry of curves. Just sayin'
Carry on all,
Gary

JoeyInCali · Feb 17, 2017

scdiveteam said:
Hi,

I have a compound taper with a very slight sweeping or curve to the contour from the butt cap to the A joint. Parabolic taper is a discription like xerox or Kleenex respectively.

I do this because I designed my A Joint dia at 1.006 with finish.

So if the butt end is 1.245 to 1.006 at the A Joint my cue is slightly thinner than most. The taper from the A Joint to the nose is conical to .854 with finish.

When straight edge is held next to the cue the air gap annulus is barely seen over the 24" profile. When rolled on the table it is basically a non issue visually.

I believe this configuration gives the cue a special feedback with a slightly thinner grip.

Of course that feedback must go hand in hand with a correct shaft taper that has a perfect flex point geometry.

JMO,

Rick

How would a straight edge of any help if that handle has a curve?

To me a compound butt taper was designed to have a fatter A-joint section AND thinner bottom.
I have no idea why your forearm taper is less per inch than the handle and that makes the handle thinner.

As far as the "parabolic" taper ( whether it is or not ), I just imagine it this way.
Hold a 30" straight edge, end to end. Bend or arch it in the middle.
There ya go, curved taper.
Now imagine that as your taper bar.
Let's just assume the joint end will be -.200 of the bottom.
But -.100 is not in the middle.
It's somewhere near 13" from the top.

LGSM3 · Feb 17, 2017

im not sure i understand parabolic with regards to how it fits within shaft taper.

im mocking it up using .845 to .512 in 29 inches. I have an un-obstructed curve with a radius of approximately 260 feet. The greater the radius the flatter the curve (straighter taper) and the lesser the radius (less than 256ish feet) it starts to go negative (hourglass) Am i understanding this correctly?

I have no idea why i'm intrigued as i rank this (parabolic) topic amongst the dumbest shit ever discussed with regards to cue building. I feel like i should be kicked in the balls for even participating in this conversation.

BarenbruggeCues · Feb 17, 2017

For me there are only 3 points of the shaft that matter. The rest all fall into place after those 3 diameters are met.

dusting off my kicking shoes.........................

shakes · Feb 18, 2017

GBCues said:
Wow, I go away for a day and look what has happened!
First of all, Todd, I hope you didn't take my post as criticism, it certainly wasn't meant to be.
What I was hoping for was the discussion that resulted.
As to Mr. Shakes, there are several of us here who have backgrounds in math and science. I have a B.S. in Mathematics, I know Kelly (MVPCues) also is well versed in the subject. I don't know the backgrounds of all the others but that doesn't mean they don't have the backgrounds to chime in. But it doesn't require any knowledge of differential equations or the calculus to discuss the geometry of curves. Just sayin'
Carry on all,
Gary

Hi Gary,

I'll be finishing a degree in Petroleum Engineering this year, and while we're a little more specialized and have to perform a little less rigorous curriculum in Math and mechanics of materials than the other disciplines, I assure you that I've been paying special attention when the things can be applied to cues. Having said that, my argument is the same as yours.

I don't think that a curved profile on a shaft or butt needs to fit the strict definition of a parabola or hyperbola to be called parabolic or hyperbolic. While exploring the math behind it may yield something important to a cuemaker later down the road may be enticing, I believe that calling a curved segment of a cue parabolic is apt, especially in a shaft as the curve will flatten out as it nears the tip end.

MVPCues · Feb 18, 2017

shakes said:
Hi Gary,

I'll be finishing a degree in Petroleum Engineering this year, and while we're a little more specialized and have to perform a little less rigorous curriculum in Math and mechanics of materials than the other disciplines, I assure you that I've been paying special attention when the things can be applied to cues. Having said that, my argument is the same as yours.

I don't think that a curved profile on a shaft or butt needs to fit the strict definition of a parabola or hyperbola to be called parabolic or hyperbolic. While exploring the math behind it may yield something important to a cuemaker later down the road may be enticing, I believe that calling a curved segment of a cue parabolic is apt, especially in a shaft as the curve will flatten out as it nears the tip end.

I appreciate your take. I understand calling the curved part of a shaft parabolic is convenient and going to be close. Close is good enough, right? Hyperbolic is also going to be very close, as well as logarithmic. In one of the previous "parabolic" threads, someone else mentioned a hyperbolic curve likely being as good or better for pool shafts, the catenary curve. That is a hyperbolic cosine curve. Here is a graph of a parabola and a catenary.

They are so close, does anyone really know what they have? That picture was taken from this site. http://mathforum.org/library/drmath/view/65729.html

I once watched a video of someone bragging that their shafts were parabolic. Then when he cut the shaft, he cut them by hand manually dialing. No taper bar or any other sort of guide. That is an extreme case of the proclamation likely not matching the product, but I just doubt it is isolated.

When people say there is a theory that parabolic shafts play better because of the reflective properties of a parabola...well...that is part of my pet peeve with the term so widely used for pool shafts.

People can proclaim whatever they want about their cues and shafts, doesn't really matter to me. I only engage in this discussion here now and then to challenge the use of the term. I don't give the subject any serious thought between these threads.

raistlinsdragon · Feb 18, 2017

Just play with a Bluegrass....and you can forget the rest.

GBCues · Feb 18, 2017

shakes said:
Hi Gary,

I'll be finishing a degree in Petroleum Engineering this year, and while we're a little more specialized and have to perform a little less rigorous curriculum in Math and mechanics of materials than the other disciplines, I assure you that I've been paying special attention when the things can be applied to cues. Having said that, my argument is the same as yours.

I don't think that a curved profile on a shaft or butt needs to fit the strict definition of a parabola or hyperbola to be called parabolic or hyperbolic. While exploring the math behind it may yield something important to a cuemaker later down the road may be enticing, I believe that calling a curved segment of a cue parabolic is apt, especially in a shaft as the curve will flatten out as it nears the tip end.

Shakes,
Any Engineering curriculum is pretty tough, so good luck at that. And, while I learned all the theory behind math, you engineers are more familiar with the applied use of it.
Yes, we are in agreement on this subject.
Gary

GBCues · Feb 18, 2017

MVPCues said:
I appreciate your take. I understand calling the curved part of a shaft parabolic is convenient and going to be close. Close is good enough, right? Hyperbolic is also going to be very close, as well as logarithmic. In one of the previous "parabolic" threads, someone else mentioned a hyperbolic curve likely being as good or better for pool shafts, the catenary curve. That is a hyperbolic cosine curve. Here is a graph of a parabola and a catenary.

They are so close, does anyone really know what they have? That picture was taken from this site. http://mathforum.org/library/drmath/view/65729.html

I once watched a video of someone bragging that their shafts were parabolic. Then when he cut the shaft, he cut them by hand manually dialing. No taper bar or any other sort of guide. That is an extreme case of the proclamation likely not matching the product, but I just doubt it is isolated.

When people say there is a theory that parabolic shafts play better because of the reflective properties of a parabola...well...that is part of my pet peeve with the term so widely used for pool shafts.

People can proclaim whatever they want about their cues and shafts, doesn't really matter to me. I only engage in this discussion here now and then to challenge the use of the term. I don't give the subject any serious thought between these threads.

Hey Kelly,
I was trying to remember the name of a curve a rope makes when you hang it from two ends - catenary! Thanks for that.
I guess I should add that when I use the term parabolic curve, I'm not referring to any curved profile on a shaft, but one that was intentionally shaped to the definition of a parabola. Perhaps that is the difference in my approach as opposed to others.
Now down to the shop.
Gary

MVPCues · Feb 18, 2017

GBCues said:
Hey Kelly,
I was trying to remember the name of a curve a rope makes when you hang it from two ends - catenary! Thanks for that.
I guess I should add that when I use the term parabolic curve, I'm not referring to any curved profile on a shaft, but one that was intentionally shaped to the definition of a parabola. Perhaps that is the difference in my approach as opposed to others.
Now down to the shop.
Gary

It's all good. This is a 95% philosophical/analytical discussion with me.

shakes · Feb 21, 2017

MVPCues said:
I appreciate your take. I understand calling the curved part of a shaft parabolic is convenient and going to be close. Close is good enough, right? Hyperbolic is also going to be very close, as well as logarithmic. In one of the previous "parabolic" threads, someone else mentioned a hyperbolic curve likely being as good or better for pool shafts, the catenary curve. That is a hyperbolic cosine curve. Here is a graph of a parabola and a catenary.

They are so close, does anyone really know what they have? That picture was taken from this site. http://mathforum.org/library/drmath/view/65729.html

I once watched a video of someone bragging that their shafts were parabolic. Then when he cut the shaft, he cut them by hand manually dialing. No taper bar or any other sort of guide. That is an extreme case of the proclamation likely not matching the product, but I just doubt it is isolated.

When people say there is a theory that parabolic shafts play better because of the reflective properties of a parabola...well...that is part of my pet peeve with the term so widely used for pool shafts.

People can proclaim whatever they want about their cues and shafts, doesn't really matter to me. I only engage in this discussion here now and then to challenge the use of the term. I don't give the subject any serious thought between these threads.

Hey Kelly,

I have not seen any of the posts that you mention, and I would be as irritated by the claims as you are. And I can't see holding the tolerances well enough on the wooden shaft along with the sanding involved after the machining to make the claims that you mention they have made. It would be an interesting endeavor, but I think it would be mental masturbation in the end.

In these contentions, I am in agreement with you as well, thank you for enlightening me on these other issues.

~Marc

Shannon.spronk · Feb 24, 2017

I dont come in this section often, but this thread was great to read. I am finishing my degree in Mechanical Engineering this year so all of these things are near and dear to me. At the beginning of the discussion I was thinking more along the lines(curves) of a catenary and it was good to see that others feel the same way.

Taper of the butt portion?

PoppaSaun

Banned

MVPCues

AzB Silver Member

Bigb'scues

AzB Silver Member

shakes

AzB Silver Member

qbilder

slower than snails

GBCues

Damn, still .002 TIR!

JoeyInCali

Maker of Joey Bautista Cues

LGSM3

Jake<built cues for fun

BarenbruggeCues

Unregistered User

shakes

AzB Silver Member

MVPCues

AzB Silver Member

raistlinsdragon

AzB Silver Member

GBCues

Damn, still .002 TIR!

GBCues

Damn, still .002 TIR!

MVPCues

AzB Silver Member

shakes

AzB Silver Member

Shannon.spronk

Anybody read this?