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View Full Version : Skid, how it occcurs?



petel
12-12-2004, 05:45 PM
I almost never get a skid when low english is used. Does a skid occur when the cue ball climbs under or over the object ball? When two balls hit their contact is a mere pin point. To go above or below that pin point (climb) by a fraction would seem that it would cause a skid. When a shot is missed to the left or right as a result of a skid, that is caused by the cue ball falling to the left or right after the climb. (This climb is so small that it would be hard to recognize and even a foreign object or excess friction could cause the climb). Is this correct? or is there a different explanation.

Cane
12-12-2004, 06:25 PM
Lemme give this a shot. What I think you're calling skid is what I call Cling. Cling is the dwell time that two balls stay "married" at contact BEFORE they release from one another allowing the OB to continue along it's path. Cling is just a fact of life in pool, or any other sport where two objects collide. Now, what happens during cling is that the two balls move together for a particular time/distance, depending on angle, speed and spin (spin on CB), so if you have a shot that you cut perfectly to a particular point, cling may carry the ball long and make it miss. I find this to be a particular problem with "pocket speed" or finesse speed shot at angles to a side pocket where your pocket opening is only ball width or just slightly larger from that angle... by that I mean, the ball is close to straight in, maybe a quarter ball hit, but you have to shoot it at finesse speed to make it fall. When the cue ball, at this slow speed contacts the object ball, the two of them move together for a slight instant, then release from each other, allowing the cue ball to then travel along its "new" path, and ,again depending on angle, speed, and spin thereby moving the OB off of the path needed to pocket the ball. How do I get around it... simple. If I have an inside angle, I shoot it just a hair long. If I have an outside angle, I shoot it just a hair short... and I do mean JUST A HAIR (well, few hairs maybe, mines not as thick as it used to be). Now, if it's say a half ball hit or more, or if I'm in a position where I can shoot the CB low, left or right, or spin it some way, I won't adjust, because the cling then becomes so minimal that it won't make the OB travel off line.

Now, you said in your post that when you hit low on the cue ball, you didn't get the skid. Well, it's the spin that's reducing the contact time between the CB and the OB. Three things affect Cling... Angle, Speed and Spin. So, the greater the angle, the less the Cling, the greater the speed, the less the cling and the greater the spin, the less the cling. Cling ALWAYS exists on ANY shot, but Angle, speed and spin reduce it to the point that you don't have to take it into consideration in most cases... however, on those really tight shots to the side where you have to slow roll to the point that your natural roll takes over on the CB before it hits the OB, then cling will become a noticable factor.

Actually, I use this to my advantage in some situations. If a pocket is blocked only very slightly by a ball (again, just a hair), I'll use finesse speed and shoot the OB to slightly graze the blocking ball and if I hit it exactlyh where I aimed it, with slow speed so that the CB has picked up natural roll on the CB, the two balls will stay married for an instant and carry just slightly along the direction the CB is travelling before they release and the OB then will travel along a clear path to the pocket.

Just my take on it as I learned from my much revered and respected Master Instructor, whose word I take on everything except which Mexican Cafe to eat in! (Just kidding, Buddy... after a bottle of Mylanta, I was in ship shape again! /ccboard/images/graemlins/smirk.gif )

Any other takes or theories on this?

Later,
Bob

nhp
12-13-2004, 01:40 AM
IMO skid is when you don't put a pure hit on the cueball, and when it hits an object ball at an angle, the object ball kind of 'turns' and doesn't follow the line its supposed to.

HallofFame
12-13-2004, 09:21 AM
<blockquote><font class="small">Quote petel:</font><hr> I almost never get a skid when low english is used. Does a skid occur when the cue ball climbs under or over the object ball? When two balls hit their contact is a mere pin point. To go above or below that pin point (climb) by a fraction would seem that it would cause a skid. When a shot is missed to the left or right as a result of a skid, that is caused by the cue ball falling to the left or right after the climb. (This climb is so small that it would be hard to recognize and even a foreign object or excess friction could cause the climb). Is this correct? or is there a different explanation. <hr /></blockquote>

You don't get skid on draw shots because the cue ball has a backward roll when it strikes the object ball and causes the object ball to LIFT up, LEAVING the cloth, which eliminates the skid.

Three ways to eliminate skid:

1. Outside english - about 1mm or 2mm's
2. Firm hit - causes object ball to lift off cloth
3. Draw - causes object ball to lift off cloth

daviddjmp
12-13-2004, 10:28 AM
In my opinion, skid is caused mostly when following the cue ball, especially when using inside english. The follow transmits unwanted backspin to the object ball during their split-second contact. This happens to me most on soft follow shots.A taste of outside english can take care of this in most cases-

Bob_Jewett
12-13-2004, 11:03 AM
<blockquote><font class="small">Quote petel:</font><hr> I almost never get a skid when low english is used. Does a skid occur when the cue ball climbs under or over the object ball? When two balls hit their contact is a mere pin point. To go above or below that pin point (climb) by a fraction would seem that it would cause a skid. When a shot is missed to the left or right as a result of a skid, that is caused by the cue ball falling to the left or right after the climb. (This climb is so small that it would be hard to recognize and even a foreign object or excess friction could cause the climb). Is this correct? or is there a different explanation. <hr /></blockquote>
First, the contact point is not a pinpoint but a patch that has been observed up to a quarter-inch in diameter. The balls flatten when they collide; the amount of flattening depends on how hard you shoot.

Skid/cling/kick almost certainly occurs when there is chalk at the contact point. It is easy to demonstrate artificial cling by chalking the balls. If you inspect the balls carefully after cling happens in a game, you will probably see a chalk spot on the cue ball (transferred from the tip) and may see what looks like a miscue in the spot.

One reason that draw doesn't seem to produce cling is that the chalk spot from that shot will tend to be cleaned off on the cloth from the backwards rotations.

The cue ball will jump up slighlty only if it has follow. There are cling shots with neither draw nor follow and then the balls will not jump at all.

There is a theory that static electricity is involved with cling/skid/kick. I believe the idea is that static makes the chalk from the tip stick to the cue ball more. I wouldn't mind studying this with a sufficiently large government grant, but I haven't figured out how to make it part of Homeland Security.

randyg
12-13-2004, 11:07 AM
Bob has a great sense of humor...randyg

Deeman2
12-13-2004, 12:37 PM
"Skid" happens!

Cane
12-13-2004, 04:11 PM
LOL... Randy, just kidding, the Mexican food was great! BUT... NOTHING beats that burger joint in downtown Richardson. That was, as the kids say, The Bomb.

seeya soon,
Bob

pooltchr
12-13-2004, 07:14 PM
Randy, maybe he wasn't kidding! I've seen grants for stranger studies than this!
Maybe the three of us could get together and apply. Universities do it all the time! Why shouldn't the country's premier billiard academy be able to do it?

Bob, I think a drastic increase in the amount of static electricy being artificially generated in pool rooms all over the country would be of great interest to homeland security!

/ccboard/images/graemlins/wink.gif
Steve

Bob_Jewett
12-13-2004, 08:10 PM
<blockquote><font class="small">Quote pooltchr:</font><hr> Randy, maybe he wasn't kidding! ...
<hr /></blockquote>
Well, I wasn't kidding about the static friction theory. When I first heard it mentioned, the writer seemed to think that static electricity would make the balls stick together, and that seems very, very unlikely physically. It does make sense that static charge could make chalk stick to the surface of the ball, though.

As for the grant, I'm too lazy to write a grant proposal, but I'd be willing to be on the research team if someone else wants to try.

petel
12-16-2004, 07:46 PM
<hr /></blockquote>

You don't get skid on draw shots because the cue ball has a backward roll when it strikes the object ball and causes the object ball to LIFT up, LEAVING the cloth, which eliminates the skid.

Three ways to eliminate skid:

1. Outside english - about 1mm or 2mm's
2. Firm hit - causes object ball to lift off cloth
3. Draw - causes object ball to lift off cloth <hr /></blockquote>

Now this is a great explanation. Thank you.

petel
12-16-2004, 08:05 PM
Hey Bob, maybe we should have a new thread "Effects of a full moon and skids". Just kidding. You made some points and I believe that the answer about hitting the ball low from HallofFame was very accurate. With regard to the cause of a skid, well that's no more than excess friction causing the ball to climb and therefore both balls would hang out together for a moment. Excess friction can be caused by something on the cloth in front of the ball, the object ball slighly higher or lower than the cue ball (indent in the cloth), imperfrction in balls or grit on the object ball (not chalk). Take a pendulum and lengthen or shorten a string and you can see (and hear) the same effects.

Bob_Jewett
12-17-2004, 01:19 PM
<blockquote><font class="small">Quote petel:</font><hr>... With regard to the cause of a skid, well that's no more than excess friction causing the ball to climb and therefore both balls would hang out together for a moment. Excess friction can be caused by something on the cloth in front of the ball, the object ball slighly higher or lower than the cue ball (indent in the cloth), imperfrction in balls or grit on the object ball (not chalk). Take a pendulum and lengthen or shorten a string and you can see (and hear) the same effects. <hr /></blockquote>
Your understanding of skid is very different from mine. I think you are totally on the wrong track with this "climb up" thing. The important thing in most skid shots is sideways friction, not vertical. Further, material in front of the ball is almost certainly not a factor in the angle of the object ball unless it is big enough to actually deflect it. If you have boulders on your table, you should brush it more often. Finally, a slightly lower or higher object ball due to depression/hills in the cloth on any normal table does not cause significant change in the cut angle. This last part is easy to demonstrate.