Stiff versus Springy Break Cue Shafts

8Ball48043

8Ball48043

Addicted to the Sport
Silver Member
My question involves the general geometry of the break cue shaft.

I have heard that you want a break cue with a whippy/springy (probably smaller diameter then the thicker/stiffer shafts used on some break cues) shaft because that would allow the springiness/whippiness of that shaft to further accelerate the cue ball upon the spring straightening out after the initial hit (the pole vaulters pole used as an analogy). This is also part of the theory behind Willee Cue's Texas Jackhammer ferrule (http://willeecue.com/Breakferrule.html)

Versus the traditional 'shaft like a tree trunk' break cue.

I'd be most interested to hear the arguments on both sides.

Thanks in advance.
 
If you want maximum energy transfer into the CB, you want a stiff shaft and hard tip.

The springy shaft you speak of, will bounce <back> off the CB at impact, decreasing the time at the instant of contact, reducing energy transfer.
 
Sounds like there could be something to the spring theory.Sorta doubtful because of the short amount of time the CB is in contact with the tip but would like to see a study of the physics involved.

A while back a top player was in the room with a break shaft that was all steal or some sort of metal or alloy.He had been working on his break and had some1 make him the shaft.I never did ask him what he learned from the experiment but my guess is any power gained from the solid hit would be negated by the low cue speed caused by the great weight of the thing.
 
stiffer the better, believe it or not stiff objects spring back to shape with more energy and force the springy wippy objects. A perfect example is a skateboarder doing an ollie, jump. He slaps the tail of the board on the ground with his back foot which intiates the spring action that pops the board into the air. I skateboarded in highschool.
 
It is interestng to me that no one this board seems to support to the springy/whippy shaft theory. Anyone else care to weigh in? Thanks.
 
It depends on what kind of breaker you are. The stiffer shaft will benefit people with more speed and power because it will lose less energy in the transfer. A shaft that is a little springy will benefit someone with a slower stroke speed and less power since the energy that was absorbed will have time to kick back. Much like how golfers with slower swings use regular flex shafts and golfers with higher swing speeds use stiffer shafts.
 
behind the bounce again

I have been thinking about isolating the tip and ferrule as WillieCue did for a totally different reason, looks like I am a little late to the table with that idea.

Maximum energy transfer is achieved by first conserving energy. Cue deflection, vibration, flex, all of these things represent a waste of energy unless you can demonstrate that the energy is actually returned to the cue ball. Even then there is a loss of energy, heat and noise are both present and both are converted energy, "lost" for our purposes.

My best break shaft configuration features a parabolic curve and a fairly fast taper in the "pro taper" area. When I asked a player with a pretty strong break to try a few breaks with one he liked it. Then he shot a few balls in and complained the shaft felt dead. Exactly what I wanted in a break cue shaft.

Hu
 
Klopek said:
IMO, the flexing happens after contact and the golf ball has already left the face of the club. I believe the reason a golfer who generates a very fast swing speed doesn't want a springy shaft is because the club might bend around and hit him in the ass. :)
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The contact is very similar with both golf and pool. Golf is just a little faster because of the much higher swing speed v. pool. The stiffer shafts allow the golfer to swing at a higher speed which will generate more energy instead of swinging slower and having to wait for the club face to catch up.
 
smoooothstroke said:
Sounds like there could be something to the spring theory.Sorta doubtful because of the short amount of time the CB is in contact with the tip but would like to see a study of the physics involved.

A while back a top player was in the room with a break shaft that was all steal or some sort of metal or alloy.He had been working on his break and had some1 make him the shaft.I never did ask him what he learned from the experiment but my guess is any power gained from the solid hit would be negated by the low cue speed caused by the great weight of the thing.
Click to expand...

Are you certain that there WAS a great weight to the thing ? You stated "steal (which I inferred you meant steel) or some sort of metal or alloy". If the some of metal or alloy was aluminum , the shaft could be quite light , yet very stiff .
In the 70's , there were quite a few companies making aluminum cues - one that stands out in my memory is Rawlings , the baseball equipment manufacturer . They didn't play particularly well , as I recall , and imparted a sort of ringing vibration to your hand when you shot , making them feel quite odd .
But strictly as a break shaft ? Maybe with a Tiger IceBreaker tip ? . . . .
now I've got to go find one of those relics.
 
8Ball48043 said:
My question involves the general geometry of the break cue shaft.

I have heard that you want a break cue with a whippy/springy (probably smaller diameter then the thicker/stiffer shafts used on some break cues) shaft because that would allow the springiness/whippiness of that shaft to further accelerate the cue ball upon the spring straightening out after the initial hit (the pole vaulters pole used as an analogy). This is also part of the theory behind Willee Cue's Texas Jackhammer ferrule (http://willeecue.com/Breakferrule.html)

Versus the traditional 'shaft like a tree trunk' break cue.

I'd be most interested to hear the arguments on both sides.

Thanks in advance.
Click to expand...

What you heard came from someone that has little understanding of the basic physics behind pool cues and hitting a ball. The first idea you need to better understand this is a correct understanding of the types of forces involved. You basically have 3 types of forces that might act on a shaft: torsional, flexural, and compression. Torsional refers to the shaft *twisting*, like the kind of pressure you would experience trying to screw in a screw using your shaft as a screwdriver. This plays almost NO role in most situations involving pool cues, so lets put that aside. Flexural strength refers to the ability of the shaft to both resist bending, resist breaking, and return to its original shape. There are specific terms to refer to each of these specific things, but we don't need to go into that. This flexural strength will vary a fair amount from shaft to shaft. The qualities you are talking about regarding a thin whippy shaft vs. a fat stiff shaft would totally fall under this category. Now if we hit pool balls with a baseball swing and the side of the cue, this would be important. But we don't. We hit them straight on with the tip, which in theory produces very little flex in the shaft. What *does* flex the shaft is hitting the cueball off center, and hitting the bed of the table and bending the shaft around your bridge. I believe, however, that if you look at high speed film of balls being hit, and do some research, these forces have very little to do with the resulting speed of the cue ball. Remember that the tip is in contact with the ball for something like 1/1000th of a second or less. During that time, the shaft may bend to to side if you hit the ball off center, but the ball is LONG GONE before the shaft snaps back to its original straight shape. SO I must tell you that these qualities will not have any noticeable effect on the speed of the cue ball.

The final type of force I mentioned is compression force. This is absolutely relevant to a pool cue hitting a ball. This force is all about the way the tip compresses at impact (essentially becoming "shorter" for an instant). This compression transfers to the ferrule and moves like a wave down the length of the shaft. Think of laying a slinky on its side on a table, slightly stretched out. If you whack one end of the slinky with a ruler, you will see a compression wave travel along the length of the slinky. This effect will be determined by many variables. The most important of these would include: tip hardness and elasticity, ferrule construction and material, woods used...to a much lesser degree the diameter of the shaft may play a tiny role in this, but I highly doubt it would be anything significant. Without question the tip will be # 1 and the ferrule # 2. The general rule of thumb is that a harder tip imparts *more speed* to the cueball. The same would be true for a harder ferrule material, denser harder shaft wood, etc. The more energy that is spent compressing these materials, the less energy is left to propel the cue ball forward.

Hence in summary, your best bet in shopping for a break cue *with the goal of increased power* would be to observe these ideas:
1) Get a shaft diameter that is comfortable to you. This will let you swing that cue faster. The better the cue feels, the more comfortable and confident you will be really laying into it and swinging fast.
2) Get the hardest tip you can. Personally, I like a tip/ferrule combination that has just a little bit of give to it. I feel this gives me better feel and control, though may rob me of a couple of tenths of a mile per hour in speed, which is irrelevant to me. A phenolic tip will almost always produce more cueball speed than a leather tip, all other things being equal.
3) Get a weight that allows you to produce the greatest momentum. By momentum I mean the combination of speed and weight. A heavy cue moving medium fast might have a similar momentum to a light cue moving very fast. You must experiment with this. I think for the vast majority of humans, a cue in the 18.5-19.5 weight will yield a great balance in this regard, and allow one to get close to his or her top speed while maintaining good "mass", thus producing a lot of momentum.

Now, that all addresses how to get *speed* out of your break cue. If you want to break *good*, that is a different conversation.

Hope this helps,

KMRUNOUT
 
MitchAlsup said:
If you want maximum energy transfer into the CB, you want a stiff shaft and hard tip.

The springy shaft you speak of, will bounce <back> off the CB at impact, decreasing the time at the instant of contact, reducing energy transfer.
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Mitch, your first statement is correct, your second statement is the opposite of correct.

A "springy" shaft (which I think means "flexible"), will not react differently at impact with the cueball than a "stiff" shaft unless the qualities that achieve the springyness or stiffness also affect the compression qualities of the shaft. Generally speaking, there will be extremely small differences in cues in the amount of time they are in contact with the cueball. This will be principally due to the hardness of the tip and secondarily due to the hardness of the ferrule. You got things backwards...a harder tip will have *less* duration of contact with the cueball, and a softer tip more. The ultimate would be to have a material that has as close to zero time of contact for maximum energy transfer. This is because if you could come up with a material that was perfectly elastic and had no compression whatsoever, it would impart the maximum energy to the cueball, and the time of contact would be zero (well, at that point you would be hitting the lower limit of contact time based on the *cueball compression*, which you can't control...so you could never get to zero).

Remember that it doesn't take any time for energy to transfer from one object to another. It's not like you are building up force over time and the more time touching, the more force. If there is any time at all at contact, this time is spent compressing the materials, which costs energy.

Didn't mean to bash your response, just thought you might enjoy a better understanding of what is going on here.

And your initial statement stands: you want a hard tip! (though the stiffness of the shaft may not be that important)
Hope it helps,

KMRUNOUT
 
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Klopek said:
The pole vaulting analogy is ineffective because the pole is being bent prior to releasing it's energy where as a break shaft bends after contact with the cue ball. The ferrule/tip may compress during contact, but the bending happens once the cue ball has left.
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Excellent observation! and well put.

KMRUNOUT
 
Junkyarddog said:
A shaft that is a little springy will benefit someone with a slower stroke speed and less power since the energy that was absorbed will have time to kick back. Much like how golfers with slower swings use regular flex shafts and golfers with higher swing speeds use stiffer shafts.
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This is not right. In the golf analogy, the golf club shaft has flexed *before* it reaches the golf ball. In the pool example, the energy absorbed *will not* have time to "kick back". Not even close.

KMRUNOUT
 
Klopek said:
IMO, the flexing happens after contact and the golf ball has already left the face of the club. I believe the reason a golfer who generates a very fast swing speed doesn't want a springy shaft is because the club might bend around and hit him in the ass. :)
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Klopek,

While your theory has merit ha ha, I believe that in a golf swing there is sufficient time for the flex in the shaft to straighten out before, or ideally *at* impact with the golf ball. When a player begins their swing, they are only really moving the grip of the club. The head of the club is "left behind", if you will. So the initial acceleration of the grip will lead the acceleration of the head of the club. The time involved in a golf swing is an eternity compared to the time involved in a pool cue-cueball collision. The whole point of different shaft flexes in golf is to find the one that corresponds to your swing speed. A golfer that swings very fast *means* that that golfer imparts a larger acceleration to the grip of the club. Thus a stiffer shaft is required to straighten out the club before or at impact.

Does this make sense?

KMRUNOUT
 
KMRUNOUT said:
This is not right. In the golf analogy, the golf club shaft has flexed *before* it reaches the golf ball. In the pool example, the energy absorbed *will not* have time to "kick back". Not even close.

KMRUNOUT
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Wouldn't the compressed tip/ferrle/wood start decompressing when the cue ball begins moving forward *during* contact and push the cue ball? When you hit the cue and the compression happens we aren't talking about a sandbag that deforms after it absorbs energy. We have an object that returns to shape after an opposite reaction. If golf doesn't work think of a tennis racket. The racket doesn't compress until contact. Yes the racket and ball give more but both compress and release. They don't just hit and die.
 
Junkyarddog said:
Wouldn't the compressed tip/ferrle/wood start decompressing when the cue ball begins moving forward *during* contact and push the cue ball? When you hit the cue and the compression happens we aren't talking about a sandbag that deforms after it absorbs energy. We have an object that returns to shape after an opposite reaction. If golf doesn't work think of a tennis racket. The racket doesn't compress until contact. Yes the racket and ball give more but both compress and release. They don't just hit and die.
Click to expand...

Yes they would uncompress. However, the majority of this would happen after the cueball is gone. What little "decompression" happens during contact (if any) is not likely to impart much speed on the cueball.

Unfortunately the tennis analogy is exactly similar to the golf analogy, as both involve *flexural* forces, not compression forces. The racket doesn't really compress at all. It flexes. And I think the racket *does* flex before impact (it must, since we are only applying a force to the grip, not the head). However, I thing this is significantly less important and extreme compared to the golf club example. The strings in the tennis racket stretch, which I suppose would fall into the compression category. However, significant research and design has gone into developing the ideal string composition and tension for a given swing speed. This same is not true with regard to pool cue tip design (as far as I know). Also, I believe the duration of contact between a tennis ball/racket is significantly longer than between a pool cue/ball.

Could a material be engineered to compress just the right amount and be able to "spring back" during contact in a pool cue tip? Maybe. Is this likely to be a significant source of cueball speed? Probably not. The simple fact that a harder tip compresses less yet gives more speed bears this out.

Hope this helps,

KMRUNOUT
 
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