Sqwerve Observation

[Colin Colenso]

Sqwerve is the combination of squirt and swerve which describes the path the CB takes when it is struck off center with some elevation. So basically, any shot that has english on it will sqwerve to some degree.

Following the discussion on how to make pivot point adjustments in this thread: http://forums.azbilliards.com/showthread.php?t=116815

I did some testing and thinking on sqwerve to see what I could learn.

A couple of things we know:
1. When hitting the CB high with english this creates a slight masse (swerve) that acts very quickly. Low english acts more slowly.
2. Low english swerves more due to the increased cue elevation. (i.e. It returns most closely toward the original cue direction). High english stays closer to the squirt line in final direction.

Something that I noticed in my testing:

In just about all practical applications the higher you hit the CB, the further away from the squirt line, and closer to the cue line you will hit the OB.

If the balls were allowed to continue their paths the opposite will be the result, but in practical use, the point at which these sqwerve paths cross is well behind the OB we are aiming at.

The diagram below hopefully makes this easier to visualize.

Colin

 

[Colin Colenso]

How this relates to the Effective Pivot Point

Based on the above observation I was able, via some testing to establish a pivot point adjustment key depending on the height the cue ball is struck with english.

Strangely enough it seems to work pretty well independent of distance, speed or cue offset. Though this hasn't been tested comprehensively.

So the total PPe Effective Pivot Point formula, as it has been refined is:

PPe = PPi + D(5-V)K + H

K = (PPe* - PPi)/15

H is the Height of hit on CB using the numbers given below in the diagram.
(Note: In most practical cases we don't need to hit higher than the 1 range. Most draw shots fit into the -1 range.

This test almost convinces me that I'd prefer to have a separate lower squirt cue for draw shots, because most draw shots I need to bridge at around 10.5 inches and for high power draw around 9.5 inches, which makes generating power difficult without a jerky stroke. For other shots, a normal cue with pivot point around 9-10 inches is quite suitable unless you like using a particularly long bridge length.

Note also, that for a low squirt cue, such as a Predator Z, I would increase the numbers in the below chart by about 33%. So they might range from 4 to -1.3. Current information suggests the Predator Z has a natural or intrinsic pivot point of between 12 and 13 inches, compared to a normal shaft which is in the 9 to 9.5 inch range.

Colin

 

[Rod]

This test almost convinces me that I'd prefer to have a separate lower squirt cue for draw shots, because most draw shots I need to bridge at around 10.5 inches which makes generating power difficult without a jerky stroke.
Colin

Well, you have way to much time on your hands. However I'd say if you can not generate power with a 10.5" bridge you need help, if that is what you're saying. I'm not sure I agree with the verbiage to explain but the chart looks reasonable. I must have way to much time myself because I can not possibly explain why I responded if that was not the case, LOL

Rod

 

[Colin Colenso]

Well, you have way to much time on your hands. However I'd say if you can not generate power with a 10.5" bridge you need help, if that is what you're saying. I'm not sure I agree with the verbiage to explain but the chart looks reasonable. I must have way to much time myself because I can not possibly explain why I responded if that was not the case, LOL

Rod

Rod,
Go make a mark at 10.5 inches on your cue and make a bridge where this sits directly on the V of your bridge. Your fingers will now be about 6 inches from the CB.

Now pivot across to play this draw shot with 1 tip of english.

Try this and then tell me you can hit power draw shots with ease at this bridge length. From my experience, most people who think they are bridging at 8 inches are actually bridging at around 12 inches. They tend to look at the distance from their fingers to the CB instead of from their pivot to the CB.

Colin

 

[ShootingArts]

typo's?

Colin,

Either I am very confused or you need to check your text and diagram for typo's. Looks to me like you are using CB instead of OB in places, the curse of abbreviations.

Hu

 

[Rod]

Rod,
Go make a mark at 10.5 inches on your cue and make a bridge where this sits directly on the V of your bridge. Your fingers will now be about 6 inches from the CB.

Now pivot across to play this draw shot with 1 tip of english.

Try this and then tell me you can hit power draw shots with ease at this bridge length. From my experience, most people who think they are bridging at 8 inches are actually bridging at around 12 inches. They tend to look at the distance from their fingers to the CB instead of from their pivot to the CB.

Colin

Well, you would be wrong Colin. In fact when I taught I suggested one should practice, a short time, at a very short (4") bridge length. It you can accelerate from there enough to draw table length then you can easily do it at 10.5 inches. Granted some people can not get that close because of finger length. Most can't because they need more room for timing.

I'll give you a triple guarantee I can easily power draw at 10.5 inches. That distance is very comfortable for me and I know how to measure. You may think not but if I get much longer I'm not comfortable because I despise a miscue. We all have our comfort range, you have yours, I have mine.

Rod

 

[Colin Colenso]

Colin,

Either I am very confused or you need to check your text and diagram for typo's. Looks to me like you are using CB instead of OB in places, the curse of abbreviations.

Hu

Thanks Hu,
I hate it when I do that. Should be all fixed now.

Like it ain't confusing enough I just scramble it up more

Colin

 

[Colin Colenso]

Well, you would be wrong Colin. In fact when I taught I suggested one should practice, a short time, at a very short (4") bridge length. It you can accelerate from there enough to draw table length then you can easily do it at 10.5 inches. Granted some people can not get that close because of finger length. Most can't because they need more room for timing.

I'll give you a triple guarantee I can easily power draw at 10.5 inches. That distance is very comfortable for me and I know how to measure. You may think not but if I get much longer I'm not comfortable because I despise a miscue. We all have our comfort range, you have yours, I have mine.

Rod

Rod,
Good to know you weren't just guessing. If you're comfortable with power draw shots at 10.5 inches that's fine. I don't think there are many pros using such a short bridge for these kind of shots.

I can hit these shots and draw 2 table lengths at 10.5 inch bridge but I feel cramped and often punch myself in the ribs on the follow through. Maybe I could get used to it with practice, but I'd rather play the same shot with a 13-14 inch bridge which I tend to think is pretty normal for power shots.

btw: It's not so much the center ball draw that bothers me at this bridge length, but moreso when drawing with significant english.

Colin

 

[Rod]

Rod,
Good to know you weren't just guessing. If you're comfortable with power draw shots at 10.5 inches that's fine. I don't think there are many pros using such a short bridge for these kind of shots.

I can hit these shots and draw 2 table lengths at 10.5 inch bridge but I feel cramped and often punch myself in the ribs on the follow through. Maybe I could get used to it with practice, but I'd rather play the same shot with a 13-14 inch bridge which I tend to think is pretty normal for power shots.

btw: It's not so much the center ball draw that bothers me at this bridge length, but moreso when drawing with significant english.

Colin

I wasn't guessing but as you said most pro's today have what I consider a very long bridge. For some it appears to be normal length. I think in part that's because 9 ball is usually played.

Rod

 

[JoeyA]

A couple of things we know:
1. When hitting the CB high with english this creates a slight masse (swerve) that acts very quickly. Low english acts more slowly.
2. Low english swerves more due to the increased cue elevation. (i.e. It returns most closely toward the original cue direction). High english stays closer to the squirt line in final direction.

Colin

Colin, is the main reason that swerve acts faster (when hitting the cue ball high) because of the general difference in speed between shooting with high versus draw?

If you hit the cue ball high with a faster stroke, will you obtain less swerve? Or, if you hit the cue ball high with a slower stroke will you obtain more swerve?

Most of my draw shots especially lengthy draw shots, I hit the cue ball with a faster stroke than I do when I am attempting to hit the cue ball with simple high, "follow english".

Your studies and information on Squerve are appreciated.
JoeyA

 

[Colin Colenso]

Similar surface speeds and the Rabbit effect.

Colin, is the main reason that swerve acts faster (when hitting the cue ball high) because of the general difference in speed between shooting with high versus draw?

If you hit the cue ball high with a faster stroke, will you obtain less swerve? Or, if you hit the cue ball high with a slower stroke will you obtain more swerve?

Most of my draw shots especially lengthy draw shots, I hit the cue ball with a faster stroke than I do when I am attempting to hit the cue ball with simple high, "follow english".

Your studies and information on Squerve are appreciated.
JoeyA

JoeyA,
The swerve takes earlier with topspin v backspin for the same reason a slow stun shot gets more throw than a fast stun shot. When the relative speeds of the surfaces are similar, the greater is the proportional influence of friction. When the CB is rolling forward on the cloth the rotational aspect can grab easily. When the CB is spinning backwards the sideways rotational aspect slips on the cloth moreso. Later as the backspin and slide dissipate the sideways rotation can get a better grip and turn the CB more. (At least that's how I understand it)

By the way, JAL thought of the word 'tortoising' to describe this effect, as in the tale where the rabbit takes off faster but the tortoise (low swerve) eventually wins. In my tests on practical shots however, where we use english to hit a CB with low cue elevation, it's the rabbit that seems to always get there first. A bit of a sprint race. Maybe this effect, of the topspin winning the race on normal shots, should be referred to as the rabbit effect while tortoising is the general term for how the CB swerves in this manner.

Colin

 

[Colin Colenso]

Bump for Monday readers.

 

[Colin Colenso]

Just a note to point out that this Rabbit effect is not just significant for users of BHE, it is a useful guide for anyone using english, however they align with it.

If you are using english, expect more deflection (squerve) the lower you hit the CB.

Also, avoid hitting the CB very high with english unless you absolutely have to because the rate of change of deflection is very sensitive to change. It's better to get used to shots that have a more constant level of total deflection. Try to hit follow shots with english by striking only 1/2 tip above the center axis and allow natural roll to accumulate on the CB as it picks up friction from the cloth.

Also, avoid center CB english unless it is a long shot and the CB will develop natural roll. A sliding CB with english creates major throw. If you must use it, try to use just a touch of english on the CB. Something close to gearing OE.

Colin