NV B.66 - The 30-degree rule, from VEPS I

[randallpaulcom]

Yes this does make sense and in most cases when I used this it worked dedending if I hit the CB correctly. It was interesting to note CB placement after contact. Something to consider when looking tho over all table. Thanks allot. I will check out your CD's

[DrDaveBilliards]

@randallpaulcom

As long as the CB is rolling when it hits the OB, the rule applies. The best thing is that even if you don't hit the OB where you are aiming, the CB will still head very close to the peace-sign direction.

Now, with more speed, you do need to shift down the tangent line, but the final angle is the same. Also, as demonstrated, the angle varies a little based on the cut angle, but that can be adjusted for also.

[randallpaulcom]

@DrDaveBilliards I also Like your explanation on Cut introduced throw I have to work on applying that deliberately as I never really thought about the friction aspectand controling that or understanding the physics. Very cool stuff Dave. I haven't played for years and now finding myself playing again so doing some catch up. I see your website and the different instructional CD's Maybe tell me which you would suggest. Send me a mail on youtube privately if you wish

RP

[DrDaveBilliards]

@randallpaulcom

Concerning the CDs or DVDs, each is described on the Product Info sheet linked on the website. You can also view excerpts from each of the products to get a feel for which you think might be the most benefit to you. Without knowing you and your goals, it is difficult form me to recommend something, but I think the website has enough info to allow you to judge for yourself.

Good luck with your game,

Dr. Dave

[MyCosmicPath]

a well calibrated peace sign :) brilliant lol

[DrDaveBilliards]

@MyCosmicPath

It definitely pays to calibrate.

[Bladerunner55217]

I have learned that the 30 degree rule is a must when playing 8ball on bar box tables !!!!!

[DrDaveBilliards]

@Bladerunner55217

Agreed. It is also useful in most other cue sports and games.

This is definitely the most useful principle of pool and billiards.

[FateAtYourWindow]

dr dave please see at 0:41 of this video "Japan Open 2010 semi final - Efren Reyes vs Tohru Kuribayashi Part 9/9": to me it seems that the cue ball had a close 3/4 cut on the 8 ball(since 8ball traveled much faster than the cue ball). yet the cue ball deflection angle seemed to be 40-45 degrees-ish. what do you think? I would have thought the angle wouldve been smaller and cue ball wouldve cut the 9ball on the other side instead.

[DrDaveBilliards]

@FateAtYourWindow

I agree. In fact, I just tried the shot on my table, and the CB did hit the other side of the 9.

In the video, the hit is probably close to a 1/2-ball hit, where the CB deflection angle is the largest. Notice where the 8-ball enters the side pocket ... he hit it about as full as he could. Also, I think there might have been a little "cling" (excessive throw) on this shot, which kills some of the CB spin and increases the deflection angle.

[FateAtYourWindow]

@DrDaveBilliards very complicated! What contributes to the "cling" and how to avoid it(i don't think the japanese player intended on that CB path, seemed like a fluke to me)? I know one way explained in your video is to use english, but english makes aiming so much harder, also, the shot was made from the cushion and english would not have been possible. Are there ways to calculate this maybe a little short video explanation would be cool!

[coinstriker]

Does speed impact the deflection much? I noticed that during the first 8 shots he had the same speed on the cue ball and the last 4 shots he slowed it down.

Thanks for the videos! :)

[DrDaveBilliards]

@coinstriker

We should have used the same speed on all of the shots for the graph to avoid confusion. Small speed differences have very little effect.

With faster speed, the CB shifts down the tangent line more before curving forward, but the final angle is still the same. We show this later in the video. For more info, see "speed effects" under "90 and 30 degree rules" in the FAQ section of my billiards DOT colostate website.

[stardustie]

hmh triangle always has 180degree corners in it when u count em together.. so one of em is 90 and it leaves 2 corners for the other 90.. because it's has a 90 degree corner the other corners have to be the same.. so the triangle is 45degrees, 45 degrees and 90 degrees. your peace sign ain't 30degrees.

[stardustie]

@stardustie atleast not in the 2:38

[ledzeppeman]

@stardustie You are a fool. Basic geometry. its called a 30 60 90. There are rules for it in classes you should take in high school to determine lengths. Use some common sense before commenting.

[stardustie]

@ledzeppeman god.. get back to school.

[Airblader]

@stardustie Let me tell you as a mathematician: one corner having 90° doesn't imply a 45-45-90 triangle. For example, 3-4-5 is a pythagorean triple (3² + 4² = 5²), which means: A triangle with 3cm and 4cm on the legs and 5cm on the hypothenuse has a 90 degree angle, but it does not have equally long legs and therefore the other 90 degrees won't split into two 45 degree angles.

[FateAtYourWindow]

@stardustie lol.... are you serious man? where's your brain dude?

[wiibert]

Mech 102 (section 002) student- Hi Dr.Dave

[DrDaveBilliards]

@wiibert

Hi back at you. Don't work on your pool game until you finish your homework due Wednesday!!! :)

Catch you later,

Dr. Dave

[wiibert]

@DrDaveBilliards can I visit the dorms and play pool before Wednesday?

[DrDaveBilliards]

@wiibert

... only if you finish your homework 1st! :(

[cfrosty6]

nice and clear, nice one!

[DrDaveBilliards]

@cfrosty6

Thanks.

Peace,

Dr. Dave

[superschema]

Good stuff!

[DrDaveBilliards]

@superschema

Thanks. Please help spread the word about my vids, website, and instructional products.

Regards,

Dr. Dave

[rickymewis1983]

this video is great but i was just wondering if you might have some a little more advanced i would like to see a video where you are compensating for different englishes and speeds

[DrDaveBilliards]

@rickymewis1983

See Disc II of the "Video Encyclopedia of Pool Shots," which covers "English and Position Control."

[rmcqn]

Very informative Dave. Have you considered filming this from the perspective of the shooter rather than the spectator, or both? When you showed your fingers on the square I held mine up to the screen to compare my 30 deg angle ... oops! upside down! Still a good lesson though.

[crrazyy]

@rmcqn  2:40