On Target Tips: low deflection and hybrid tips.

[Colin Colenso]

This is an interesting thread to me since I have argued with Dr. Dave in the past about the values of previously-conducted squirt tests - both robotic, and manual. I had maintained that squirt could be almost entirely eliminated as long as the tip struck the cue ball above the horizontal axis, and is struck with as level a cue as possible.

So, in my quest to prove my own theory on this matter, I built a fixture that would allow me to hit the cue ball at a consistent height above the horizontal center line (1/2 tip), and at a consistent butt elevation (clearing the rail by 1/2-inch). A few minutes ago, I finished my first round of tests. I started out by testing a one-piece graphite cue because I figured it would be the stiffest, and highest end mass cue I could find. To my surprise, it delivered a highly noticeable amount of squirt. (Remember, I have been thinking that squirt could be almost entirely eliminated with this type of hit.) So, I tested it over and over, and found that the exact speed of stroke, and maybe a few other unseen and/or undetected variables, gave varying results in the amount of squirt produced.

Then I tested a Predator 314. This time, I was again surprised. The 314 still produced squirt (just as dr. Dave has reported it will), but it was not significantly less than the graphite cue. As near as I could tell, it was only about 1/8th of an inch over a distance of 70-inches. But again, results varied with speed and those other unseen and/or undetected variables.

My point here is twofold. For starters, when I earlier thought I was eliminating squirt with a "proper" hit, I really must have been subconsciously "steering' the cue ball to make it go where I wanted it to go. And second, I believe that everything that has been said about the inaccuracies of both manual and robotic testing, are true. One set of tests by either method does not conclusively prove a whole lot. Even my own testing has not really proven anything to me, other than the fact that my previous theory was wrong.

Roger

Hi Roger,
I've done a lot of squirt testing as I've developed and exclusively use back hand english. What you are saying about negating squirt is true, but the variables involved in its execution are much harder to control than the system I use.

The biggest issues are speed of shot and degree of english. If you're 1mm off on where the cue strikes the object ball, it will change the line of shot considerably, and if you go from a slow to a fast shot, there will be variation as well.

This doesn't even take into account that playing position often requires side spin with stun and draw.

If you try some shots at various speeds and greater and lesser degrees of side spin (offset from center), I think you'll get an idea what I'm talking about.

From my experience, BHE works best with low deflection cues, though on some soft long shots, the bridge length becomes awkwardly long to accommodate the effective pivot point.

Yours is an interesting approach though. I'll consider it and see if I can find some practical applications for it in game play. I generally avoid hitting very far above center unless it is a power shot, due to the early swerve effect. On slowere shots, I can hit at the center line and natural roll gathers over a foot or so.

 

[askalf]

I don't think a tip of any design can "overcome" the amount of squirt (cue ball deflection) created by a shaft (conventional or LD).

If designing a robotic tester, the test bed and cue support structure should be designed to have the cue be perfectly level at impact with the CB. Then the squirt measurements would not depend on speed, distance, or cloth conditions, because there is absolutely no swerve with a perfectly level cue, regardless of how much sidespin is used.

http://dbkcues.ru/articles-2/cue-testing-unit/?lang=en

 

[Petros Andrikop]

http://dbkcues.ru/articles-2/cue-testing-unit/?lang=en

Really impressive work!!

 

[dr_dave]

While I appreciate Dr Dave's efforts, unfortunately, we are coming at this problem from two completely different perspectives.

His goal is to test and isolate for the physics principle best described as squirt, or two massive object colliding not on the center plane and the resulting change in direction from the incoming object due to the off center hit.

Sorry, but your description of my "perspective" is not very accurate. My goal is to help people better understand the effects of squirt and swerve so they can better understand how to make aiming adjustments during play for a wide range of typical shot speeds, shot distances, sidespin amounts, cue elevations, and playing conditions (regardless of what equipment they might be using).

My Goal: to help pool players more easily adjust for off center aiming difficulties due to effective squirt with a more inexpensive method than has been available in the past.

There are several free ways to adjust aiming to deal with "effective cue ball deflection" (the combined effects of squirt and swerve). One approach is to use back-hand english (BHE) and front-hand english (FHE) when appropriate. These techniques can work with any equipment with proper choices for bridge length and/or cue elevation (for given shot speeds and distances).

Having said this, I still think people will be interested in trying out your two-material tips. Even though my careful experiments showed no reduction in squirt for the tip you sent me, I still think your tip is a cool idea, and I'm sure people will be interested in trying them out. Some people might like the different feel it can provide with different shots.

I sincerely wish you luck and success with your marketing and sales.

Best regards,
Dave

 

[dr_dave]

Colin,

It's great to see you back on the forum. I hope you stay around for a while. When I think of posters who have contributed the most interesting and useful insight over the years, your name is definitely near the top of the list.

BTW, even though Jaden's tip doesn't seem to reduce squirt (based on the testing results in the video I posted), I agree with you that his design is innovative and represents good out-of-box thinking.

Catch you later,
Dave

Thanks Dave,
I watched your video and it did make me wonder about the potential of reducing squirt with strength / hardness / reduced sideway compression type methods. I guess that's still to be proven.

I can see potential in lower mass materials in the tip core to reduce tip end mass.

I expected to see bigger differences in squirt in the wide range of tip hardnesses, height, and types I tested in the video based on the info at the bottom of the what causes squirt resource page, but the data didn't show much difference. However, if an effective tip material could be found that is really hard and really light, maybe the tip could make a bigger difference.

It's great to see Jaden doing some exciting experimentation with materials!

I agree 100%. It often baffles me that after 200 years or so since the leather tip was invented, we still haven't found a tip material that does a better job.

Best regards,
Dave

 

[Jaden]

that may not be your intention. ..

Sorry, but your description of my "perspective" is not very accurate. My goal is to help people better understand the effects of squirt and swerve so they can better understand how to make aiming adjustments during play for a wide range of typical shot speeds, shot distances, sidespin amounts, cue elevations, and playing conditions (regardless of what equipment they might be using).

There are several free ways to adjust aiming to deal with "effective cue ball deflection" (the combined effects of squirt and swerve). One approach is to use back-hand english (BHE) and front-hand english (FHE) when appropriate. These techniques can work with any equipment with proper choices for bridge length and/or cue elevation (for given shot speeds and distances).

Having said this, I still think people will be interested in trying out your two-material tips. Even though my careful experiments showed no reduction in squirt for the tip you sent me, I still think your tip is a cool idea, and I'm sure people will be interested in trying them out. Some people might like the different feel it can provide with different shots.

I sincerely wish you luck and success with your marketing and sales.

Best regards,
Dave

I'm sorry Dave that may not be your intention but when you only test for one speed of hit that is your result. Your use of only a super hard stroke effectively isolated squirt in an attempt to better minimize swerve; however, the vast majority of shots by people are medium speed shots, not super hard. That gives people a false sense of how much of a difference their tips affect their shots on the majority of the shots they shoot. There's a reason that most better players like their tips cut really short and its not all in their head.

I would suggest you go back at some point and do tests with hard stroke medium strokes and soft strokes to see the difference.

Your attempt to isolate squirt I think takes away from your results.

I'm guilty of that too as my initial tests were all a medium stroke because I knew that swerve is maximized on soft strokes and that hard strokes are also affected due to increased force.

Jaden

 

[dr_dave]

I'm sorry Dave that may not be your intention but when you only test for one speed of hit that is your result. Your use of only a super hard stroke effectively isolated squirt in an attempt to better minimize swerve; however, the vast majority of shots by people are medium speed shots, not super hard. That gives people a false sense of how much of a difference their tips affect their shots on the majority of the shots they shoot. There's a reason that most better players like their tips cut really short and its not all in their head.

I would suggest you go back at some point and do tests with hard stroke medium strokes and soft strokes to see the difference.

Your attempt to isolate squirt I think takes away from your results.

Jaden,

IMO, if testing a shaft or tip for how much squirt (cue ball deflection) it produces so it can be compared to other shafts or tips, one should be measuring squirt only. Ideally, this would be done with a robot that has the cue perfectly level, with a consistent hit on the horizontal axis of the CB. In that case, there would be absolutely no swerve, and the resulting squirt measurements and comparisons would be very accurate and consistent. The results would not depend on CB speed (which can vary with the type and hardness of tip, even for a fixed cue speed), the exact cue elevation, or the cloth conditions (which can vary with cleanliness, temperature, and humidity, all of which can change during a set of tests).

If you or others claim to have a low-squirt shaft or a low-squirt tip, the only true test is to directly measure the amount of squirt without possible corruption of data and results by swerve which can vary with cue elevation, cue speed, tip hardness/efficiency, and ball and cloth conditions.

I agree with you that when playing, the cue will always be elevated some and swerve will be a factor, and the player will need to be able to adjust for swerve effects which vary with shot speed, shot distance, cue elevation, and conditions. However, if your goal is to measure how much squirt reduction a shaft or tip provides, the tests should measure squirt directly. I would always doubt results from any cue or tip tests where swerve is a potential factor because any slight changes in cue elevation, CB speed, and/or cloth conditions can significantly affect the results. That's why it is best to try to eliminate or minimize swerve when doing squirt testing. There are too many variables involved with swerve.

Now, if people want to see how "effective cue ball deflection" (AKA squerve, or the combined effects of squirt and swerve) vary with speed, then I would agree that varying the shot speed (but keeping the cue elevation constant) during the tests would be a good idea. But then you would be measuring how swerve varies with shot speed. You wouldn't be measuring or comparing the amount of squirt the shaft or tip produces. Also, you would get different results on different cloths, under different conditions, at different cue elevations.

In the testing procedure I recommend in the video I posted, swerve is minimized by keeping the cue as level as possible, using a horizontal-axis hit on the CB, and by using fast speed. Without having a robot with a perfectly level cue, this is the only way to reliably measure shaft/tip squirt independent of all of the swerve effects that can potentially produce misleading results. If our CB speeds varied a little, it wasn't a big deal because the swerve doesn't change much with small changes in speed at such fast speeds. However, if much slower speeds were used instead, and if the speed varied even a small amount (maybe because a harder tip resulted in more CB speed even for a repeatable and consistent stroke), then the swerve could vary quite a bit from one shot to the next (especially if the cue elevation were also changing slightly) and the results could be misleading.

Regards,
Dave

 

[Cornerman]

I'm sorry Dave that may not be your intention but when you only test for one speed of hit that is your result.

Ah! Now I figured out what might be going on.

I think the basis of the soft-core concept as far as decreasing squirt is concerned is to retard the ability of the transverse wave down the shaft. That is to say that part of the contact time, the outer edge of the tip and resultant lateral wave initiation has to fight through the soft core just to really start the propagation down the shaft. Less propagation length means less shaft mass involved.

It is very possible that the act of shooting hard closes that initial "fight through" time in a significantly shorter period of time compared to a medium stroke that unfortunately on firm shots, the normal amount of transverse wave propagation occurs.

I think Dr. Dave needs to at least test at medium speeds as a comparison. By the same token, I think Jaden needs to test at higher speeds to see if he also sees the spike in squirt.

The issue with the floating ferrule concept (which also works to retard the initiation of the transverse wave propagation) is that once the float gap is closed (presumably on very firm shots), then the full tenon and shaft are in play.

Freddie

 

[dr_dave]

Ah! Now I figured out what might be going on.

I think the basis of the soft-core concept as far as decreasing squirt is concerned is to retard the ability of the transverse wave down the shaft. That is to say that part of the contact time, the outer edge of the tip and resultant lateral wave initiation has to fight through the soft core just to really start the propagation down the shaft. Less propagation length means less shaft mass involved.

It is very possible that the act of shooting hard closes that initial "fight through" time in a significantly shorter period of time compared to a medium stroke that unfortunately on firm shots, the normal amount of transverse wave propagation occurs.

Before I did the tests, I also had a bunch of ideas for how Jaden's tip design might help reduce squirt (for more info, see the bottom of the what causes squirt resource page); but until we see conclusive and reliable experiment data proving reduced squirt, independent of swerve effects, it is all conjecture.

I think Dr. Dave needs to at least test at medium speeds as a comparison.

If I had the time and desire, and if I hadn't already imposed on my cue technician, I would do this, but I would not be very confident in the results due to everything mentioned in my previous posts. Although, if somebody builds or has a cue-testing machine that can produce several repeatable speeds, and do so with a level cue, I would love to the see the results.

Catch you later,
Dave

 

[The Renfro]

Interesting conversation going on.... If you wanted to test at low or medium speeds why not take the bed cover off?? Elevation and speed won't have a thing to do with creating swerve since without friction there should be none....

Low and medium speeds just mean that swerve is a factor and at just the right speed and elevation won't all tips be net zero? Granted the speed and elevations would be different and the elevation and speed are likely dependent variables..... more speed meaning more elevation to get to net zero....

Matter of fact at super slow speed and lots of elevation you could say the tip was not zero deflection but negative deflection if you are talking about the net movement based on your aim, but that would mean redefining deflection to include deflection and swerve and since they are 2 separate phenomenons it's mixing apples and oranges...

I know from my soft version that it has a higher spin to speed ratio than my hard or medium... It spins the ball more at all speeds... I would hazard a guess that at slow to medium speeds it would have more swerve because of that fact and would show a lower net cue ball movement as well.... The same may be true with the Kamui Super Softs and we are also on track as to why Kamui tried to market their chalk as low deflection. more spin....

Chris

 

[Rackemep]

subscribing so I can find this later...