A Little Help With Math Please

Johnnyt

Johnnyt

Burn all jump cues
Silver Member
I think most on here have read that the contact to contact points target is only 3mm.

I am a contact aimer by feel. I can't believe I hit that point every time I run 50 balls or 4 racks of 9 ball. I mean on 41/4" pockets I look at the contact point on the OB and try to hit it. There has to be a wide tolerance of something like +/- 3mm. I tried to do the math myself but I just get a headache. I know my stroke can't be as straight as it once was, but I just look for the contact points, get down and 2 or 3 stroke it in.

I think if the brain can do this 50 times in a row it's amazing. Honestly, I don't really aim my pool shots like I do a rifle.

Would some wiz at math figure the leeway (+/-) we have he ball go in. I hope I got my point across. Thank you in advance. Johnnyt
 
Try holding the OB against the CB and look at where they touch..The contact point is tiny..

Now, if you lay them on a table close to the pocket, you have up +-2" in which to hit the OB to make it in the hole..

Put them at the other end of the table and there is basically zero tolerance from the actual contact point.
 
Wybrook said:
Try holding the OB against the CB and look at where they touch..The contact point is tiny..

Now, if you lay them on a table close to the pocket, you have up +-2" in which to hit the OB to make it in the hole..

Put them at the other end of the table and there is basically zero tolerance from the actual contact point.
Click to expand...

So the tolerance depend on the distance and angle? Johnnyt
 
Johnny, the contact point is not 3mm. The area of the tip that contacts the cb is 3mm. Same size as the circle on a red circle cb.

And, yes, the farther away from the pocket the ob is, the less margin of error there is on the contact point.

edit: You can look here for margins of error graphs. http://billiards.colostate.edu/threads/cut.html#margin
 
Try the Pool Shot Analyzer java app from the downloads page of www.cue-md.com. It'll tell you almost everything you want to know about contact point size, margin of error, cut angles and so on.





Johnnyt said:
I think most on here have read that the contact to contact points target is only 3mm.

I am a contact aimer by feel. I can't believe I hit that point every time I run 50 balls or 4 racks of 9 ball. I mean on 41/4" pockets I look at the contact point on the OB and try to hit it. There has to be a wide tolerance of something like +/- 3mm. I tried to do the math myself but I just get a headache. I know my stroke can't be as straight as it once was, but I just look for the contact points, get down and 2 or 3 stroke it in.

I think if the brain can do this 50 times in a row it's amazing. Honestly, I don't really aim my pool shots like I do a rifle.

Would some wiz at math figure the leeway (+/-) we have he ball go in. I hope I got my point across. Thank you in advance. Johnnyt
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Adam gave you you a good answer.

The margin for error changes.

Don't get down on yourself. You are as good as you are.

The subconscious mind is an amazing entity if our conscious mind can just stay of it's way.

Best 2 You & Yours...

& All.

PS The 3 mm you may have been thinking about is what 'they' say is the approximate area diameter of contact between the CB & cue tip.
 
ENGLISH! said:
Adam gave you you a good answer.

The margin for error changes.

Don't get down on yourself. You are as good as you are.

The subconscious mind is an amazing entity if our conscious mind can just stay of it's way.

Best 2 You & Yours...

& All.

PS The 3 mm you may have been thinking about is what 'they' say is the approximate area diameter of contact between the CB & cue tip.
Click to expand...

Thank you, Adam, and the others for answering my question. Johnnyt
 
ENGLISH! said:
Don't get down on yourself. You are as good as you are.

That's the horrible thing about this game - I keep hoping that I would be as good want to be, or even as good as I think I am, but the sad fact remains that I am only as good as I as am.

Gideon<----Thinking of Popeye for some reason.
Click to expand...
 
Johnnyt said:
I think most on here have read that the contact to contact points target is only 3mm.
Click to expand...
You're thinking of the contact area of the tip hitting the CB. The contact area of two balls colliding is much smaller.

...on 41/4" pockets I look at the contact point on the OB and try to hit it. There has to be a wide tolerance of something like +/- 3mm.

...

Would some wiz at math figure the leeway (+/-) we have he ball go in.
Click to expand...
If you want to know the size of the contact area on the OB allowing for pocket slop, it depends on a few things:
- pocket opening size
- angle of approach to pocket (changes effective pocket size)
- OB distance from pocket

For a spot shot into your 4 1/4" corner pockets (~36" at optimal approach angle), the OB contact area is about 1/16". The table below shows some more. (NOTE: These results are all for optimal approach angles, which don't exist at the larger distances.)

pj
chgo

P.S. If you want to know the overall margin of error including CB accuracy needed to hit the OB contact area, you have to include:
- cut angle
- CB distance from OB

View attachment 17094
 

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Last edited:
Just to complicate things, the angle into the pocket has a lot to do with it as well. If you are on line with the spot going into one of the close corner pockets, then you are approaching the pocket at its widest opening. If you are going down the rail, the "size" of the pocket is dramatically decreased. And the farther away the object ball is from the intended pocket, the smaller the margin of error becomes.
 
Patrick Johnson said:
You're thinking of the contact area of the tip hitting the CB. The contact area of two balls colliding is much smaller.


If you want to know the size of the contact area on the OB allowing for pocket slop, it depends on a few things:
- pocket opening size
- angle of approach to pocket (changes effective pocket size)
- OB distance from pocket

For a spot shot into your 4 1/4" corner pockets (~36" at optimal approach angle), the OB contact area is about 1/16". The table below shows some more.

pj
chgo

P.S. If you want to know the overall margin of error including CB accuracy needed to hit the OB contact area, you have to include:
- cut angle
- CB distance from OB

View attachment 17094
Click to expand...

Wow, thank you. I think I'll just keep not thinking when aiming. Johnnyt
 
Johnnyt said:
So the tolerance depend on the distance and angle? Johnnyt
Click to expand...

I believe you know this answer, but YES.

100% of your margin of error depends on your angle to the pocket, pocket size and the distance from it.

That margin of error equates to the amount of OB "contact point" you can hit to still make the ball.
 
distance from the hole would play a big part how much leeway you have...a ball hit at the same angle on the same plane from further down table might miss by a diamond compared to the 10 in shot that was initially taken. not sure about a 3mm spot...
 
Patrick Johnson said:
You're thinking of the contact area of the tip hitting the CB. The contact area of two balls colliding is much smaller.


If you want to know the size of the contact area on the OB allowing for pocket slop, it depends on a few things:
- pocket opening size
- angle of approach to pocket (changes effective pocket size)
- OB distance from pocket

For a spot shot into your 4 1/4" corner pockets (~36" at optimal approach angle), the OB contact area is about 1/16". The table below shows some more. (NOTE: These results are all for optimal approach angles, which don't exist at the larger distances.)

pj
chgo

P.S. If you want to know the overall margin of error including CB accuracy needed to hit the OB contact area, you have to include:
- cut angle
- CB distance from OB

View attachment 17094
Click to expand...

This attachment is horribly incomplete. This only works for approaching the pocket in the limited angle where the entire mouth of the pocket is visible.
 
Oversimplifying it a bit don't you think? What about the speed at which you hit the shot? If the angle to the pocket involves hitting any part of the rail, speed affects whether or not the ball drops. Also, the felt and rails affect those angles as well. Balls tend to slide in off the rail easier on newer cloth, etc.

I doubt you can ascertain any useful/accurate metrics for this, unless you only include margin of error for making shots that never touch any part of the rail. There are way too many variables that make it dependent on the specific table at a specific time.

Patrick Johnson said:
You're thinking of the contact area of the tip hitting the CB. The contact area of two balls colliding is much smaller.


If you want to know the size of the contact area on the OB allowing for pocket slop, it depends on a few things:
- pocket opening size
- angle of approach to pocket (changes effective pocket size)
- OB distance from pocket

For a spot shot into your 4 1/4" corner pockets (~36" at optimal approach angle), the OB contact area is about 1/16". The table below shows some more. (NOTE: These results are all for optimal approach angles, which don't exist at the larger distances.)

pj
chgo

P.S. If you want to know the overall margin of error including CB accuracy needed to hit the OB contact area, you have to include:
- cut angle
- CB distance from OB

View attachment 17094
Click to expand...
 
ElCorazonFrio said:
This attachment is horribly incomplete. This only works for approaching the pocket in the limited angle where the entire mouth of the pocket is visible.
Click to expand...
Yes, that's what it says. No reasonably sized chart could include the OB contact areas for all approach angles, so these are just the best case examples.

pj
chgo
 
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