Break tip and cue weight questions answered by Dr. Dave

[td873]

That's not exactly true. If you can stroke a heavier cue at the same speed as a lighter cue (which isn't as easy as it sounds), the cue ball speed will be significantly faster with the heavier cue. See the discussion and plots on pages 9-11 in TP A.30.

The type of tip can also make a significant difference. A phenolic tip can provide about 17% more break power/energy than a typical medium-hardness leather tip (see the bottom of page 10 in TP A.30).

Regards,
Dave

I think the "exactness" of the statement depends on if you are a mathematician or a layman.

I think I understand the graph on p.9 of TP_A-30, but there is an equal chance I don't.

​

It appears that there is an increase in cue ball speed for a heavier cue, but unless I'm misunderstanding the graph, it doesn't appear(to me) to be significant (or at least at the same proportion as cue weight increases). For example, the graph seems to illustrate that for an 11 oz different in cue weights (14-25), there is only around a 18%-19% overall difference in cue ball speed (as a percentage of stick speed). So if you have a 14 oz cue, the cue ball is travelling 1.21X faster than the stick. For an 18 oz cue, 1.31X faster and for a 25 oz cue, about 1.39X faster.

This 18-19% difference in overall velocity is less than the actual increase in stick weights (25oz cue 178% heavier than a 14oz cue). This comparison is probably not an analogous one. But if you look at it from the angle of velocity difference between common cues at a pool hall (say between 17oz and 22 oz), there is only around 7% difference in cue ball speed (~129% for the 17 oz cue vs ~136% for the 22 oz cue) when cue weight increases by 29% (increasing cue from 17oz to 22oz (5oz) is around 29% increase in mass).

I think this understanding is confirmed in the commentary under the graph that says "Notice that for a given cue speed, more cue weight gives more cue ball speed, as one would expect. Although, the benefit of the added weight diminishes at at [sic] higher weights."

And, looking at the graph on p. 10, although the overall cue ball speed percentages are higher, it appears that the slope of the line representing the change in percentages is about the same.

My reading is that for every ounce heavier you go, you get around a 1.4% [relative] increase in cue ball speed.

I'm not smart at the maths, but I stayed at a Holiday Inn once, so there is a 10% chance I'm reading those graphs right.

-td

 

[Old Nine Baller]

If you can break at the same speed with a heavier cue than a lighter cue, use the heavier cue.

Mattie

I'm going to take a few liberties with your post, I hope you don't mind too much:smile:.

First of all I'm guessing that you are talking about open-breaking 8, 9, or 10 ball racks. I'm assuming you want the best break possible and you figure that the speed the cueball hits the rack (all other things being equal) is a high priority.

I wish that all the very knowledgeable people who've responded in this thread would state very simply, for the masses, just exactly the difference between using a heavier vs. lighter cue to break with, given the same break speed.

I'm going to exaggerate here for the purpose of illustration but the point will be made (I hope).

If you could triple the weight of your break cue and still break at the same speed then you would do 3 times the damage (work) to the rack.

If you left the weight of your cue as it is and tripled the speed of your break you would do 9 times the damage (work) to the rack.

The work done by a moving mass increases as the square of the velocity. This is the reason for "corked" (lighter) baseball bats in MLB, it allows faster bat speeds to drive the ball farther.

I just thought that someone should've made this clear, in layman's terms, quite awhile ago.

ONB

 

[zpele]

Well don't take my word for it, read the write up that Chris Renfro did on my break tip based on his tests.

Also, Dave only tested my LD tips with a hard hit, it did not test for average hits which is what I tested them for.

They DO reduce effective squirt but Dave has stated that he does not have the means to do the comprehensive testing for them.

Had I known that his intention was to only do hard hit tests, I would've declined his offer to test. Only hard hits attempts to isolate variables while my intent is to improve the end use for players as they typically use them.

It's the same with worrying about the physics of the break, (no offense meant here Dave), but when Dave can break better than me, then you should take his advice over mine, until then, you should listen to the people who have tried my break tips.

Oscar Dominguez, Rob Saez, and Joey Gray to name a few...All of whom loved them.

Jaden

This is a bunch of hooey...

Everyone knows that harder hits produce more deflection. Why would you even use a term such as 'medium' when a medium speed shot is subjective to the player?

If your claims about your tip reducing squirt are true it wouldn't matter what speed you hit the ball at. When compared to another tip hit at the same speed it should deflect less.

Not to feed the fire but I defer to Dave heavily on this one. Independent tests are usually the most trustworthy...

 

[Jaden]

It's not hooey...

First off, the tips that I sent Dave were secondary designs, the first designs that I originally tested and had the best results with could not stand up to the rigors and stresses(long term).

Secondly, the only tips that I have even been willing to sell are the jump/break which are NOT low deflection, are and never were intended to be, etc...

Thirdly, my original design was never meant to be low deflection.

It was meant to be impossible to mushroom. Pushing back the pivot point of the shaft (lower deflection) was something I noticed when testing some of the original prototypes.

Since then, testing has meted out that certain shafts react differently, especially really high deflection whippy shafts and especially on hard shots. I admit I jumped the gun a little bit on sending the tips to dave. I had only tested them on two shafts and only on an average speed hit.

I was never intending on selling the tips as low deflection tips until I ensured that all ducks were in a row and I won't.

I have since redesigned them again to overcome the materials issue and will be doing further tests and be sending out trial samples to select people for testing themselves.

In the mean time, the jump break tips are available but I am not pushing promotion on them yet.

Jaden

p.s. I'm trying to keep my cool but people need to word their posts a little more carefully, do NOT suggest that I am a liar or that I am incompetent. I am neither and do not appreciate the inference that I am. I have not suggested that about anyone else, so I suggest the same courtesy be applied.

Making tips is NOT my profession. I do it because I love the game and if I can make things that help people I'm going to.

 

[dr_dave]

I think the "exactness" of the statement depends on if you are a mathematician or a layman.

I think I understand the graph on p.9 of TP_A-30, but there is an equal chance I don't.

...

View attachment 359625​

...

I'm not smart at the maths, but I stayed at a Holiday Inn once, so there is a 10% chance I'm reading those graphs right.

-td

Your understanding seems fairly good.

The only thing I would add is that "breaking power" is more directly related to CB energy, which is proportional to the square of CB speed.

If increasing cue weight from 17 to 22 oz (with a fixed cue speed) increases cue ball speed from 129% to 136% of the cue speed, this is actually an increase in speed of 5.4%:
(136-129) / 129 * 100 = 5.4%
This corresponds to an effective increase in breaking power of 11.1%:
(136^2 - 129^2) / 129^2 * 100 = 11.1%

To a top player, a 10% increase in breaking power would be considered "significant;" although, I can see how somebody might think this is a small increase for such a large change in cue weight.

But again, all of these numbers assume a player can generate the same cue speed with a heavier cue as compared to a lighter cue (which we know is not usually the case), so added weight might not be as beneficial as the numbers imply (unless a person's muscle physiology and technique actual allows the person to get fast speed with a heavy cue).

Interestingly, based on the numbers in TP A.30, changing from a medium-hardness leather tip on a playing cue (typical COR = 0.73) to a phenolic tip on a break cue (with a COR as high as 0.87), can have an even bigger effect, creating an increase in breaking power of 17%. I would certainly consider this "significant."

Catch you later,
Dave

 

[dr_dave]

If you could triple the weight of your break cue and still break at the same speed then you would do 3 times the damage (work) to the rack.

Not really. See the previous post. The advantage of more cue weight is not as large as some people might think. Also, there is a limit to how much cue weight can help (see the plots and conclusions in TP A.30 if you want proof or more info).

Having said this, every individual will have a personal ideal cue weight that will allow that person to generate the most breaking power (due to an ideal combination of fast speed and cue weight). For more info, see the optimal cue weight resource page.

If you left the weight of your cue as it is and tripled the speed of your break you would do 9 times the damage (work) to the rack.

I think that is a fair statement, assuming you can maintain accuracy and not have the CB bounce too high at the faster speed.

Regards,
Dave

 

[JB Cases]

how can cue ball be going faster than cue stick just before impact...when the cue ball is just sittin there? (snicker)

He meant that the speed that the cue is moving just before impact. Imagine a car going 100mph and it hits you and you accellerate to 150mph.

If it were say a small car you might only reach 130 mph but if a big car you might reach 150mph as you body flies through the air.

 

[Old Nine Baller]

how can cue ball be going faster than cue stick just before impact...when the cue ball is just sittin there? (snicker)

He meant that the speed that the cue is moving just before impact. Imagine a car going 100mph and it hits you and you accellerate to 150mph.

If it were say a small car you might only reach 130 mph but if a big car you might reach 150mph as you body flies through the air.

Where does the input of energy come from?

ONB

 

[Old Nine Baller]

Not really. See the previous post. The advantage of more cue weight is not as large as some people might think. Also, there is a limit to how much cue weight can help (see the plots and conclusions in TP A.30 if you want proof or more info).

Having said this, every individual will have a personal ideal cue weight that will allow that person to generate the most breaking power (due to an ideal combination of fast speed and cue weight). For more info, see the optimal cue weight resource page.

I think that is a fair statement, assuming you can maintain accuracy and not have the CB bounce too high at the faster speed.

Regards,
Dave

Dave,

I consulted a physics book, charts are not necessary. The "work" done increases in proportion to the weight increase but as the square of the speed increase.

ONB

 

[dr_dave]

For those interested, I've updated both the optimal cue weight resource page and TP A.30 based on some additional calculations and plots, and based on the discussion in this thread.

Check them out,
Dave

PS: You might need to use the Refresh or Reload feature in your browser to see the new versions if you have viewed the documents recently.

 

[Hits 'em Hard]

p.s. I'm trying to keep my cool but people need to word their posts a little more carefully, do NOT suggest that I am a liar or that I am incompetent. I am neither and do not appreciate the inference that I am. I have not suggested that about anyone else, so I suggest the same courtesy be applied.

Making tips is NOT my profession. I do it because I love the game and if I can make things that help people I'm going to.

You've made a lot of claims that aren't backed up with science. I've asked you to explain how your break tip is able to negate squirt when accidental hitting of left or right. You imply that it has some sort of magical power to turn a off center back into a center hit. I want explanations to how you can make the claims you do. Not bullshit reviews. Cold hard science facts. Currently your words are just pixie dust.

No one has called you a liar or incompetent, yet. But the audacity you have to make the claims you do with no evidence to back those claims up is where the problem is. When you don't hit the head ball square there is a loss of energy that cannot be regained by choosing a different tip. You make claims that go against all current understandings of ball collisions and energy transfer. I'd like to see you explain with evidence why the tip does what you claim. Of course you'll just call me a troll and ignore the request to provide evidence.

 

[dr_dave]

I've asked you to explain how your break tip is able to negate squirt when accidental hitting of left or right. You imply that it has some sort of magical power to turn a off center back into a center hit.

Actually, this can be done with any shaft and with any tip, provided your bridge is at the natural pivot length of the cue. A demonstration of this can be found at the :2:04 point in the following video:

NV B.71 - Cue natural pivot length and back-hand english (BHE), from VEPS II

The effect is also described and illustrated (Diagram 4) in the following instructional article:

"Squirt - Part IV: BHE, FHE, and pivot-length calibration" (BD, November, 2007)

Regards,
Dave

 

[Jaden]

You're confusing TWO different discussions...

You've made a lot of claims that aren't backed up with science. I've asked you to explain how your break tip is able to negate squirt when accidental hitting of left or right. You imply that it has some sort of magical power to turn a off center back into a center hit. I want explanations to how you can make the claims you do. Not bullshit reviews. Cold hard science facts. Currently your words are just pixie dust.

No one has called you a liar or incompetent, yet. But the audacity you have to make the claims you do with no evidence to back those claims up is where the problem is. When you don't hit the head ball square there is a loss of energy that cannot be regained by choosing a different tip. You make claims that go against all current understandings of ball collisions and energy transfer. I'd like to see you explain with evidence why the tip does what you claim. Of course you'll just call me a troll and ignore the request to provide evidence.

One is the discussion on the tech that allows for decreased effective cueball deviation from the original aimline.

The other is energy transfer based on the materials used.

The break tip that I make isn't anything special, it's simply made of a material that is very hard, and therefore has good energy transfer, but also has good grip characteristics which results in fewer miscues...

The LD tip I make originally was designed using the same material for my break tip on the periphery of the tip with a softer leather in the center.

This allowed, on off center hits, for the energy to be transferred closer to the center of the shaft which allows for less deviation of the cb from the original aimline.

The reason behind this is the only thing in contention, but because it uses a different method from reduced end mass for the same result, it is less effective than reduced end mass on harder struck shots because the energy isn't transferred to the center of the shaft as easily on harder struck shots.

The problem is that the design that is the most effective doesn't have any internal support where the softer leather is. This makes it fail after prolonged use.

I was forced to redesign it or expect people to replace it once every two weeks. It couldn't be manufactured at low enough cost for this to be effective.

I went back and redesigned it. The original design was MUCH more effective as a LD tip, but the ones that I sent Dave were early prototypes of the new design. They had not been fully tested and I was therefore not aware of the issue with harder struck shots.

I have since been forced to redesign it again because of materials issues.

It's possible that there won't be an effective way to make the LD tip. It won't matter, that will only change the marketing strategy.

There are still benefits to the new design besides lower deflection. In fact, I may even reverse the design so that the softer material is on the outside with a harder core material or offer both.

I am still experimenting and seeing what these designs yield.

Regardless of that, the jump/break tip IS fully tested and does exactly what is advertised. Everyone who has hit with one has attested to that.

Vilmos Foldes road partner recently got one from me as well.

We'll see where it goes. I'm confident the new one will work and will have excellent properties that aren't currently available in other tips. Whether or not it will have reduced squirt properties remains to be seen.

I have been delayed in my experimentation and testing and prototyping because as I have stated, making tips is NOT my profession. Life comes up and prevents us from doing the things we love sometimes.

Jaden