Tip radius... bad idea

nineballsafety8

nineballsafety8

6ft 5" 285, hits 'em hard
Silver Member
So, I have been contemplating how to post this for a week, and still can't quite wrap my head around how to explain this without confusing everyone, but I will give it my best shot.

Often when discussing tips, the first question is "what radius do you like, dime or nickel"... well while this is easy to gauge, and if all shaft diameters are the same, is a fair assesment of what you may like.

However, the idea of a set radius ONLY works on a given shaft size, and here is why.

I have several shafts in my arsenal... my main shaft is 13.3mm, and I have 3 more 12.7, 12.2, 11.7, 11.5

What I discovered is, that every shaft that I have, has a DIFFERENT radius on it. The reason for this, is that a given radius (lets use nickel for arguments sake) have different curvatures on different size tips.
On a 13.3mm shaft a nickel radius has a fairly steep curve and will allow a high degree of spin to be applied to the cue ball, but conversely a nickel radius on a 11.75mm shaft is pretty darn flat, and disallows a high degree of spin to be applied.

A better way of "thinking about tip radii" is the the about the tangent vector that the curve departs the edge of the tip. What this means is, if you think about the angle that the tip ends where the curve meets the edge of the tip, you will get a much more consistent curvature if you have different size tips, on several shafts.

I had several diagrams drawn up to help explain this, but am at work and cannot attach the photos. I hope this makes sense to you all, and maybe someone else good jump in and give their opinion (and if you understand, help with the illustration)
 
nineballsafety8 said:
So, I have been contemplating how to post this for a week, and still can't quite wrap my head around how to explain this without confusing everyone, but I will give it my best shot.

Often when discussing tips, the first question is "what radius do you like, dime or nickel"... well while this is easy to gauge, and if all shaft diameters are the same, is a fair assesment of what you may like.

However, the idea of a set radius ONLY works on a given shaft size, and here is why.

I have several shafts in my arsenal... my main shaft is 13.3mm, and I have 3 more 12.7, 12.2, 11.7, 11.5

What I discovered is, that every shaft that I have, has a DIFFERENT radius on it. The reason for this, is that a given radius (lets use nickel for arguments sake) have different curvatures on different size tips.
On a 13.3mm shaft a nickel radius has a fairly steep curve and will allow a high degree of spin to be applied to the cue ball, but conversely a nickel radius on a 11.75mm shaft is pretty darn flat, and disallows a high degree of spin to be applied.

A better way of "thinking about tip radii" is the the about the tangent vector that the curve departs the edge of the tip. What this means is, if you think about the angle that the tip ends where the curve meets the edge of the tip, you will get a much more consistent curvature if you have different size tips, on several shafts.

I had several diagrams drawn up to help explain this, but am at work and cannot attach the photos. I hope this makes sense to you all, and maybe someone else good jump in and give their opinion (and if you understand, help with the illustration)
Click to expand...
Not at all... The radius determines the arc and a nickel radius is the same arc on any sized shaft

If your tip arc does not align with the arc of a nickel then you do not have a nickel radius... Very simple
 
joelpope said:
Not at all... The radius determines the arc and a nickel radius is the same arc on any sized shaft

If your tip arc does not align with the arc of a nickel then you do not have a nickel radius... Very simple
Click to expand...

I understand that the arc is the same... I am stating that the given arc on different size tips, work differently.
 
figured out how to upload the pic

the radius on both of these illustrations are IDENTICAL (copied and pasted same image)
but as you will note, on the skinny shaft, the radius appears much flatter, whereas the fatter shaft has a much more emphasized curve
tip radii.png
 
nineballsafety8 said:
I understand that the arc is the same... I am stating that the given arc on different size tips, work differently.
Click to expand...

I've been playing a long time and I never understood all that dime nickel stuff. I mean, unless the sides of the tip are not parallel to each other, you would have to visually deform a 12.75 ferruled tip to end up with a dime radius. Like in a pencil sharpener maybe. :D
 
Indeed, I overlayed the arcs to verify. When they are overlayed you can see that the only difference is arc length. It is this arc length that you see as more emphasized but the actual contact area would not be changed at all. Only about 3mm of leather contacts the cueball.
 
mark187187 said:
The curvature is the same for all nickle radius tips. The smaller the tip radius though, the less of the curve is present. For example, if the tip was the same width as a nickle, the tip would be a semi-circle, representing half of a nickle. If the tip was half this wide, the tip would be the shape of a quarter-circle. The curvature would be the same though, since a nickle is a perfect 360°circle. The larger tip would appear more curved, only because you could see more of it.

Practically, all nickle radius tips have the same curvature, and if we took a similar size section of a selection of tips, say a 10mm width, they would appear uniform.

When we come to play, the entire tip never makes contact with the cue ball. I'd estimate that at most, approximately 1/3rd of the tip give or take makes contact. So, when using a nickle radius on a range of tip sizes, the portion of the tip striking the cue ball on each would have the same size and curvature, and the cue ball would react similarly.

Sent from my GT-I8190N using Tapatalk
Click to expand...

You are correct, and this is the exact point that I was making.
A nickel radius IS the SAME arc, however, it will perform COMPLETELY differently on different size tips.
This is where the tangent vector comes into play.
tip radii 2.png
Imagine using max spin, with both tips... the larger shaft will impart much more spin that the smaller shaft, as the tangent vector of the larger shaft is much greater
 
nineballsafety8 said:
figured out how to upload the pic

the radius on both of these illustrations are IDENTICAL (copied and pasted same image)
but as you will note, on the skinny shaft, the radius appears much flatter, whereas the fatter shaft has a much more emphasized curve
View attachment 345645
Click to expand...

What you'd have to do to match the correct tip shape is to shrink the wider one in till it's the same width as the thinner shaft, then stick it on top of the cue.

I like the illustration you did, very easy to see what you mean.
 
I think an important part of this discussion is the "other" arc,,, meaning the arc of the cue ball... the wider shaft won't be able to hit as low on the cue ball,, meaning, by the logic of the points made, the arc of the cue ball will be less. However, the narrower shaft will hit lower on the cue ball, therby having a contact point which has a greater arc (again by the logic of that cool diagram above).
My feeling is if you could achieve the much greater arc on the wider shaft (as shown by the tangent line above) to make contact with the (in theory) same location the narrower tip can contact (but it can't because the table gets in the way),, it would result in a miscue. The collective angles are too steep.
My head hurts.
 
nineballsafety8 said:
You are correct, and this is the exact point that I was making.
A nickel radius IS the SAME arc, however, it will perform COMPLETELY differently on different size tips.
This is where the tangent vector comes into play.
View attachment 345657
Imagine using max spin, with both tips... the larger shaft will impart much more spin that the smaller shaft, as the tangent vector of the larger shaft is much greater
Click to expand...

First, the radius' are the same. A nickel is a nickel.

Second, yes they do look different as in your drawings. The reason is that the radius is extended further to reach the side of the ferrule.

Last, it doesn't matter. The reason is about contact point. In you're drawing, your assuming that you can get all the way out on the edge of the tip, meaning that the larger diameter shaft would give a different contact angle because it's further down the radius. But, in reality, you can't get that far out with either tip size. You would miss cue long before you get that close to the edge of the tip. I'm not familiar with the actual formula to calculate this, but it's often over looked. It's very common to think that we can get all the way out to the edge of the tip when in reality we really can't.


Royce
 
haystj said:
I think an important part of this discussion is the "other" arc,,, meaning the arc of the cue ball... the wider shaft won't be able to hit as low on the cue ball,, meaning, by the logic of the points made, the arc of the cue ball will be less. However, the narrower shaft will hit lower on the cue ball, therby having a contact point which has a greater arc (again by the logic of that cool diagram above).
My feeling is if you could achieve the much greater arc on the wider shaft (as shown by the tangent line above) to make contact with the (in theory) same location the narrower tip can contact (but it can't because the table gets in the way),, it would result in a miscue. The collective angles are too steep.
My head hurts.
Click to expand...

You logic is "somewhat" correct... You are stating that the smaller shaft is able to hit further to the edge of the cueball, without the table getting in the way.

However a cueball is 2.25" in diameter, and the maximum distance from center ball you can hit without a miscue is 1.125" (half the diamter of the cueball).. which converts to 28.575mm.... meaning there is a remaining 28.575mm of cueball outside of the contact point with the tip.
Assuming you used a maximum tip size of 14mm (largest legal tip size in BCA rulebook) this would still allow for 14.575mm of space outside of the tip to not hit the table.
 
nineballsafety8 said:
Y
However a cueball is 2.25" in diameter, and the maximum distance from center ball you can hit without a miscue is 1.125" (half the diamter of the cueball).. which converts to 28.575mm.... meaning there is a remaining 28.575mm of cueball outside of the contact point with the tip.
Assuming you used a maximum tip size of 14mm (largest legal tip size in BCA rulebook) this would still allow for 14.575mm of space outside of the tip to not hit the table.
Click to expand...

1.125" from center ball would be the bottom of the ball. Actual miscue limit is about half that.
 
The plural for radius is either radii or radiuses in the English language.
I have also heard it referred to, {incorrectly} as circlety parts in the south. Early from Squidbillys comes to mind.
 
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neither one of those in the picture is a nickel radius as measured by a nickel. first is too flat and second too round. and the second one is too fat to use as a measurement as shafts arent that thick. the nickel works in the range of common shaft sizes. it isnt for all sizes of a circle.

slide your nickel up the shaft and see how that lines up with your tip top. if it is nickel shaped you are right on.
 
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maha said:
neither one of those in the picture is a nickel radius as measured by a nickel. first is too flat and second too round. and the second one is too fat to use as a measurement as shafts arent that thick. the nickel works in the range of common shaft sizes. it isnt for all sizes of a circle.

slide your nickel up the shaft and see how that lines up with your tip top. if it is nickel shaped you are right on.
Click to expand...

you understand that both curves are the same right....?
 
nineballsafety8 said:
you understand that both curves are the same right....?
Click to expand...

An 11.75 tip is to flat with a nickle radii.
An 13.25 tip is to rounded with a dime radii.

Once a 13.25 tip wears down a little the edge
of a dime radii curve reaches right down to the
ferrule. You wouldn't have any tip side left to burnish.

A cue maker told me once the ferrule diameter tells
you what size radii to put on the tip.

Now have at it, this will be my only reply in this thread.
Enjoy ! :thumbup:
 
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