# how to design a true parabolic/conical tapered cue- ?

#### JoeyInCali

##### Maker of Joey Bautista Cues
Silver Member
In the elastic collision, the ball does not bounce Joe or foul by hitting twice. It stays on the cue ball for a period of time based on the velocity and hardness of the tip. If there is any deflection in the shaft as a rod the tip will move laterally randomly causing squirt if any left or right hand english was part of the aim point by the player.
Squirt is caused by the end mass .

#### BarenbruggeCues

##### Unregistered User
Silver Member
Hi,

I am the biggest fan of DPK. He is the Tiger Woods of Cuemakers.

On my Esoteric Cue Design the first 12 inches of the butt from the joint to the A Joint is conical .850 to .1004. From 12" to 29 I have a slight constant parabolic curve to the end. If you put a straight edge against my profile you see an air gap.

Also IMO, the best shaft taper has three major segments.

1. From 0 to ten inches
2. From 10 inches to 15"
3. From 15" to 29".

If you have the good playable geometry, the cue will flex at 6 to 8" from the tip when you bend it while you hold two fingers on top of the shaft and your thumb underneath on the very ends of the shaft.

Why is this important?

The flex point needs to be in the area of your bridge hand which acts as a steady rest. Why? Because when the tip contacts the stationary cue ball the shaft wants to deflect behind the bridge at the moment of inertia if the taper does not have a strong climb at the #2 segment of the total profile geometry 35 to 40 thou from 10 to 15".

If you shaft bends closer the the middle it negates the steady rest effect of a closed bridge and just a slight deflection toward the center of the shaft will cause the tip to move on the cue ball during what Newton refers to the elastic collision. Depending on the velocity it can squirt and apply unintended english on the ball. And the player does not even understand what happened when the object ball misses the pocket. Bad equipment will not make you get better no matter how many L drills you perform.

From 15" to the joint, the geometry can be anything you want as long as you land on the number of the joint dia. Here is where the shaft can incorporate a parabolic taper or as some refer the the coke bottle.

Again, these observations are based on physics. The interpretation I have just stated are only my approach to this subject. If the reader does not agree, please just agree to disagree with me because I will not get into any pissing matches.

Of coarse this steady rest effect is not as effective with an open bridge but the described geometry above will still out perform any shaft that flexes closer to the center.

BTW, the next time you have a Cog or Gina shaft at hand, try the test and observe with your own eyes.

So my advise to new cuemakers is if your shafts bend toward the center, go back to the drawing board.

I will not share my geometry numbers but a good place to start your investigation is to mic a Predatator Z Shaft as your start point.

Rick
Bad equipment will not make you get better
If the reader does not agree

Don't worry rickie, no one will agree and copy your precious numbers. You are almost correct....bad equipment can make you bad.

Funny how some of the most mundane of numbers used in creating a playing cue are some of the most sought after worldwide. Yet there is always someone trying to reinvent the wheel.
My advice is to steer clear of this type of typical misinformation when trying to achieve a playable billiards cue. Smoke and mirrors at best.
Just because you idolize a past or present cue builder doesn't make you a fraction of what they have achieved.

#### JC

##### Coos Cues
Good shaft tapers are like obscenity as observed by the late supreme court justice Potter Stewart.

Hard to exactly define but you know it when you see it.

#### scdiveteam

##### Rick Geschrey
Silver Member
Bad equipment will not make you get better
If the reader does not agree

Don't worry rickie, no one will agree and copy your precious numbers. You are almost correct....bad equipment can make you bad.

Funny how some of the most mundane of numbers used in creating a playing cue are some of the most sought after worldwide. Yet there is always someone trying to reinvent the wheel.
My advice is to steer clear of this type of typical misinformation when trying to achieve a playable billiards cue. Smoke and mirrors at best.
Just because you idolize a past or present cue builder doesn't make you a fraction of what they have achieved.
Hi Dave,

The basis for the information that I took the time to share here was not something I thought about from speculation or from contemplation of my navel. I also was very careful to say it was my opinion.

Reinvent the wheel? I think not, It was shared with me by someone everybody reading this would agree is one of the best living cuemakers In the world.

So you can direct your notable and predictable cyisysim at me all you want and I am fine that.

You know Dave, I made a statement here many years ago in this forum calling your over top reaction to something I posted as Nazi like censorship. These forums are for open discussion and sharing info. At the time is was just a catch phrase I used but when I learned you were a from Germany I immediately apologised to you in public and asked for your forgiveness with the hope it could be resolved and maybe someday if we met somewhere we could be friends.

You rejected my offering which was unfortunnate and have continued to troll every single post I have ever made without exception.

You attempt to seek some kind of revenge is not healthy for you or anyone else who walks down that path.

My best advice to you is: When one seeks revenge, it is like taking poison and hoping the other person dies.

I am a Christian. I know I hurt your feelings years ago, apologised and asked for your forgiveness. It is still my hope that if we ever meet and I hold out my hand to you in friendship that you might reconsider.

BTW, I am a jazz piano player and Oscar Peterson and Bill Evan's are what I consider to the pinicle in that art form and are genius by their nature. That does not translate into I think I will ever reach their level of artistry. I am from Chicago and I can tell you without question, that DPK is also a genius by nature. You can agree or disagree.

So sue me if I look up to and give Kudos to people who I think are tops in their field sir.

Now is the time for my friend Joey to say, "let me get the popcorn". LOL

I apologize to OP for this diversion from the topic.

And like Forest Gump, "that is all I have to say about that".

Ricky

#### JC

##### Coos Cues
I'm so out of touch I don't even know who DPK is. I guess he made a hell of a shaft?

#### HawaiianEye

##### AzB Silver Member
Silver Member
I'm so out of touch I don't even know who DPK is. I guess he made a hell of a shaft?

David Paul kersenbrock began making pool cues in 1972 in Illinois. Through the years he was instrumental in helping Jerry Franklin at Southwest, and also with Omega cues.

Hall of Fame International Cuemakers Association

David Paul Kersenbrock: Inducted 2009
David started building cues in 1972. David has worked with several cuemakers including Hall of Fame members Bert Schrager and Jerry Franklin. He also built cues with Omega/DPK from 1990 to 1996. David popularized the 3/8-11 thread wood to wood joint. It had the flat bottom minor diameter thread like Harvey Martin had used, but David put a starter pilot and center hole on the end of the pin. David pushed manual pantograph inlaying cues to new levels by free handing inlays instead of using template patterns. He used high magnification optics and a very steady hand to accomplish this. David and Jerry Franklin developed the table saw tapering machines that are popular today. David also wrote a cue building manual and hired himself out as a trainer to many smaller cuemaking shops over the years. His cuemaking designs, styles and methods have greatly influenced the custom cuemaking industry across in the USA and around the world.

#### JoeyInCali

##### Maker of Joey Bautista Cues
Silver Member
I'm so out of touch I don't even know who DPK is. I guess he made a hell of a shaft?
Invented the first saw taper machine.
You should have seen they sold after shutting down Omega. It was massive.

#### JoeyInCali

##### Maker of Joey Bautista Cues
Silver Member
Good shaft tapers are like obscenity as observed by the late supreme court justice Potter Stewart.

Hard to exactly define but you know it when you see it.
I can't see until and I get the shaft between two hands and do the bending test .
Haha!
I've thrown many softies . Many moons ago some dude here sold a ton of maple blanks to my late mentor and a few guys . I ended up with a few dozens . They were mostly clean .
But, were whippy.