Is deflection effected by length of stroke?

[CaptainJR]

First I'd better define what I mean by deflection. I'm talking about the amount the cue ball goes (deflects) off line, caused by using english.

I've missed a couple firmly shot, longer english shots lately so I was practicing them last night. I think I made some progress. One thing that seemed to help right away (not a surprise, already new this just seemed to be ignoring it for some reason) was taking a shorter stroke and using a shorter bridge. This restricts how hard I can hit the shot but that could be a good thing. After not that long I was making the shots rather well. I'm talking 'with english' now, not center ball hits.

Anyway, was it my imagination? Was the amount of deflection lessened by taking a shorter stroke and or shortening the length of my bridge? Maybe I just was more accurate because of this but it really did seem to me the amount the cue ball deflected was effected. So it seemed like I had to compensate less.

 

[pooltchr]

I think you answered your own question. A shorter bridge length and stroke is probably allowing more accuracy in where you are contacting the cue ball. With a longer bridge/stroke, it's possible you are getting farther out on the cue ball than you thought you were.
S
Just a thought.
Steve

 

[Andrew Manning]

I was under the impression that how hard you hit the cue ball affects the amount of squirt for a given cue and given tip offset. If I'm not mistaken, then maybe the explanation is that shortening your bridge caused you to stroke softer, which could mean less deflection. Also I'll second what Steve said about placing your tip more accurately on the cue ball with a shorter bridge; you need to really know where you're hitting the cue ball to test the effects of deflection, and it's hard to be precise with a longer bridge.

-Andrew

 

[jsp]

Was the amount of deflection lessened by taking a shorter stroke and or shortening the length of my bridge?

If you're using BHE (backhand english), then a shorter bridge would probably appear to decrease the amount of squirt (deflection), given that you contact the same point on the CB. What you're actually doing is not changing the amount of squirt, but changing your cue's angle of entry to the CB, making it more shallow with respect to the tangential surface of the CB.

But if you're not using BIH...if you're keeping the exact same stroke line for both cases, but just adjusting your bridge, then the current theory says that your bridge length shouldn't matter. I would think that it would actually slightly increase the amount of squirt, because you're effectively adding a bit more "end mass" to the tip of your cue by shortening your bridge.

Not sure. Maybe the pivot-point masters can chime in to the discussion.

 

[Colin Colenso]

Edit: Noticed jsp's post after I saved this...hence the repetition

There is also the possibility that you are getting some BHE effect here. Hard to know without seeing how you align and stroke.

But if you tend to align and then pivot slightly to get the english, or if you swipe across the ball a little when playing english, then with a shorter bridge, the effect will be send the CB slightly in the opposite direction to the squirt....reducing the squirt deflection effect.

When using BHE, on power shots I pivot with a shorter bridge length of say 10", whereas for softer shots 15 - 20" bridge cancels out the squirt.

If you are aligning parallel, it shouldn't make a difference how long your bridge is.

 

[CaptainJR]

If you're using BHE (backhand english), then a shorter bridge would probably appear to decrease the amount of squirt (deflection), given that you contact the same point on the CB. What you're actually doing is not changing the amount of squirt, but changing your cue's angle of entry to the CB, making it more shallow with respect to the tangential surface of the CB.

But if you're not using BIH...if you're keeping the exact same stroke line for both cases, but just adjusting your bridge, then the current theory says that your bridge length shouldn't matter. I would think that it would actually slightly increase the amount of squirt, because you're effectively adding a bit more "end mass" to the tip of your cue by shortening your bridge.

Not sure. Maybe the pivot-point masters can chime in to the discussion.

Good answer jsp (and Colin). I think your right. Yes, I use BHE. So it is my imagination or just an optical illusion type of thing. I sort of wondered if that might be the case but it was so convincing that I thought I'd ask the question.

Thank you
JR

 

[TheBook]

I always thought about why the CB doesn't react the same as a OB when hit in the same spot. I hope that I can get my thought across. Stroke and hit a object ball at 9 o'clock or with 2 tips of left center english. You are hoping or wanting the ball to go straight ahead. Now, if you could mount a CB on the end of your stick replacing the tip and have the CB hit that OB ball in the same spot it would result in a cut shot of about 25 degrees.

Now the variables is the difference in mass and friction between the CB and the tip. Everything else is constant. Same stick, stroke, force, etc.

Why does the ball react differently in both cases? Is it due to the mass or the friction?

 

[Billy_Bob]

The way I understand squirt or cue ball deflection, is that there is a "sideways battle" between the tip of the cue and the cue ball.

The tip of the cue is placing a "sideways" force or pressure on the cue ball when using english. You are hitting the side of the ball.

And if the tip end of the cue is lighter or has less mass, then the cue ball wins the fight and the tip of the cue is forced sideways - the cue ball stays on course.

When the tip of the cue is heavier or has more mass, then the tip begins to win the battle and will force the cue ball sideways a little.

Thus the lighter less mass Predator deflects the cue ball less.

And with more speed, I would expect the cue ball to be forced sideways more. (For every action, there is an equal and opposite reaction.)

Imaginary Experiments...
Hit extreme edge of cue ball with tip (miscue), cue ball goes sideways. Hit center of ball, cue ball goes straight.

Hit extreme edge of cue ball with straw, cue ball goes nowhere, straw deflects off of ball.

Roll bowling ball so it hits edge of cue ball. Bowling ball keeps going straight, cue ball deflects off to side. (Bowling ball has more mass than cue ball - bowling ball wins battle.)

Repeat experiments faster or slower.

 

[Gabber]

First I'd better define what I mean by deflection. I'm talking about the amount the cue ball goes (deflects) off line, caused by using english.

I've missed a couple firmly shot, longer english shots lately so I was practicing them last night. I think I made some progress. One thing that seemed to help right away (not a surprise, already new this just seemed to be ignoring it for some reason) was taking a shorter stroke and using a shorter bridge. This restricts how hard I can hit the shot but that could be a good thing. After not that long I was making the shots rather well. I'm talking 'with english' now, not center ball hits.

Anyway, was it my imagination? Was the amount of deflection lessened by taking a shorter stroke and or shortening the length of my bridge? Maybe I just was more accurate because of this but it really did seem to me the amount the cue ball deflected was effected. So it seemed like I had to compensate less.

"Is deflection affected by length of stroke?"


No.

"length of bridge ?"

Quite possibly.

Gabber

 

[Colin Colenso]

Good answer jsp (and Colin). I think your right. Yes, I use BHE. So it is my imagination or just an optical illusion type of thing. I sort of wondered if that might be the case but it was so convincing that I thought I'd ask the question.

Thank you
JR

It's not an illusion, it is a real physical effect.

Hitting harder increases the amount of squirt.

Shortening the bridge length, then pivoting, increases the angle of the cue for the same amount of english.

The two roughly cancel each other out.

There are still complications with speed affecting throw and swerve, but basically, if you shorten the bridge for higher speed hits, you'll have more success with the aim and pivot (BHE) method.

 

[Colin Colenso]

I always thought about why the CB doesn't react the same as a OB when hit in the same spot. I hope that I can get my thought across. Stroke and hit a object ball at 9 o'clock or with 2 tips of left center english. You are hoping or wanting the ball to go straight ahead. Now, if you could mount a CB on the end of your stick replacing the tip and have the CB hit that OB ball in the same spot it would result in a cut shot of about 25 degrees.

Now the variables is the difference in mass and friction between the CB and the tip. Everything else is constant. Same stick, stroke, force, etc.

Why does the ball react differently in both cases? Is it due to the mass or the friction?

The basic answer, though perhaps not using the correct terminology, is that tip to CB collisions grip about 99% (slip 1%), whereas ball to ball collisions grip just 2% (slip 98%).

The mass of the objects has nothing to do with it. If a CB was leather coated and covered in chalk, and slid into an OB, it would grip to it, basically pushing it in a line similar to the line it was travelling, rather than deflecting it away in the direction of the line through the centers of the two balls.

 

[pete lafond]

The basic answer, though perhaps not using the correct terminology, is that tip to CB collisions grip about 99% (slip 1%), whereas ball to ball collisions grip just 2% (slip 98%).

The mass of the objects has nothing to do with it. If a CB was leather coated and covered in chalk, and slid into an OB, it would grip to it, basically pushing it in a line similar to the line it was travelling, rather than deflecting it away in the direction of the line through the centers of the two balls.

Good analogy with the leather ball. In fact this is on the opposite side of inside english (ignore the curve effects) and draw (over follow would also be considered here) were a more accurate deflection of OB and CB occur. Creates a skid off the ball rather than natural grab.

 

[mnShooter]

I don't think you're actually increasing the squirt. You are just getting less swerve because of the higher rate of velocity. Thus the shorter bridge length to compensate.

 

[Cornerman]

One thing that seemed to help right away (not a surprise, already new this just seemed to be ignoring it for some reason) was taking a shorter stroke and using a shorter bridge. This .

What was your normal bridge length? What is the shorter bridge length? Could be that your shorter bridge length coincides with the pivot point.

Fred

 

[Colin Colenso]

I don't think you're actually increasing the squirt. You are just getting less swerve because of the higher rate of velocity. Thus the shorter bridge length to compensate.

Swerve, as well as reduced Spin Induced Throw (SIT) at speed have been used to explain away the suggestion that increased hit speed increases throw.

It seemed / seems the general consensus among the physics types was that squirt doesn't increase with speed. But I don't buy it...I couldn't be more certain that it ain't true.

There is no real foundation for the claim that increasing speed doesn't increase squirt...not that I could find anyway, and I haven't come across any proponents of the theory that are willing to actively defend / debate it.

Jal, Mike Page and Bob Jewett probably know more about the evidence / debate.

I'm just a young buck who likes to rock the boat...enough to fall out sometimes

 

[mikepage]

The way I understand squirt or cue ball deflection, is that there is a "sideways battle" between the tip of the cue and the cue ball.

The tip of the cue is placing a "sideways" force or pressure on the cue ball when using english. You are hitting the side of the ball.

And if the tip end of the cue is lighter or has less mass, then the cue ball wins the fight and the tip of the cue is forced sideways - the cue ball stays on course.

When the tip of the cue is heavier or has more mass, then the tip begins to win the battle and will force the cue ball sideways a little.

Thus the lighter less mass Predator deflects the cue ball less.

I think this description is spot on so far.

And with more speed, I would expect the cue ball to be forced sideways more. (For every action, there is an equal and opposite reaction.)

Do you mean therefore more squirt for more speed? If so then this is not right. It's true a faster stick will produce more sideways (squirt) force to the
cueball. But the cueball's also moving forward faster by about the same proportion. So the squirt *angle* is roughly the same. When we talk about an anount of squirt, we're not really talking aboiut the size of the sideways force on the cueball; rather, we're talking about the ratio of the sideways force to the forward force.

The simple theory predicts no speed dependence of squirt. Some people claim there is a speed dependence. But because it's not an easy thing to measure or separate from other effects, I'd say the jury's still out on the issue.


mike page
fargo

 

[CaptainJR]

What was your normal bridge length? What is the shorter bridge length? Could be that your shorter bridge length coincides with the pivot point.

Fred

I would guess my normal bridge length is between 6 and 8 inches. When I say shorted I'm taking it to 3 to 4 inches. I think most pivot points are farther back than what I use ever. (unless a ball is in the way or something)

To others - remember I'm only talking about very firm shots. You know, when you really have no choice but to put some real juice on the cue ball.

 

[unknownpro]

Swerve, as well as reduced Spin Induced Throw (SIT) at speed have been used to explain away the suggestion that increased hit speed increases throw.

It seemed / seems the general consensus among the physics types was that squirt doesn't increase with speed. But I don't buy it...I couldn't be more certain that it ain't true.

There is no real foundation for the claim that increasing speed doesn't increase squirt...not that I could find anyway, and I haven't come across any proponents of the theory that are willing to actively defend / debate it.

Jal, Mike Page and Bob Jewett probably know more about the evidence / debate.

I'm just a young buck who likes to rock the boat...enough to fall out sometimes

Here's a question for all you guys. Can you deflect the cueball more than half a ball width at any speed or distance? Great video, btw, Colin!

unknownpro

 

[Colin Colenso]

Here's a question for all you guys. Can you deflect the cueball more than half a ball width at any speed or distance? Great video, btw, Colin!

unknownpro

Glad you enjoyed the vid ukp

If you mean deflect from the line parallel to the line of the cue, then yes...a couple of inches maybe possible over a table length.

But, if you're using BHE, and shoot much too hard and with too long a bridge, half a ball width over a table length is probably at the extreme limit.

Usually, when someone messes up using BHE by not adjusting enough for the speed, they aren't more than a couple of millimeters away from where they aimed before the pivot.

Not sure if that's exactly what you wanted to know.