Keep Smaller Tips Rounder

[Patrick Johnson]

As tip sizes trend smaller I'm sure people are finding that smaller tips work better if they're a little more "rounded". Here's why.

You need an arc on your tip that spans a little more than 60 degrees (1/6 of a whole circle) in order to use maximum spin without hitting right on the tip's edge. Every tip width doesn't do that with every tip curvature.

Here's a pic of my own (embarrassingly dirty) 10mm tip compared to the curvatures of different size US coins (with 60 degree arcs marked on each). The only coin that's "round enough" to encompass 60 degrees in less than 10mm is a dime (far left in the pic). Any flatter than that and I'm hitting on the tip's edge too soon.

The dimensions above each tip are the minimum tip widths necessary with each curvature in order to use maximum spin without hitting on the edge of the tip. For example, a nickel shape works best with a tip more than 11mm wide - a quarter shape (pretty flat), more than 12mm.

pj
chgo

 

[hurricane145]

I have one 13.5 mm shaft.
I try to keep it the same curvature as an A78x13 Goodyear Polyglas tire.

I most usually go with the curve of a nickel at 13mm or close to it.

 

[a1712]

Isn't a dime radius a dime radius whether it's a 10mm or 14mm shaft? Brian.

 

[Patrick Johnson]

Isn't a dime radius a dime radius whether it's a 10mm or 14mm shaft? Brian.

Yes, and a dime radius will work on any common size shaft/tip. But a flatter shape, like a nickel or quarter, won't work as well on smaller tips. The smaller the tip, the rounder the shape should be.

pj
chgo

 

[HawaiianEye]

Isn't a dime radius a dime radius whether it's a 10mm or 14mm shaft? Brian.

LOL.

Don't make the pool scientist have to answer any difficult questions.

 

[buckets]

Thanks for this!

 

[TheBasics]

Patrick Johnson, Howdy;

So, basically what you imply is that if my tip is 12 mm, then I should be
looking for something between a penny (19.05 mm), and a nickle (21.21 mm),
as 19.05 X 0.60 = 11.43 mm, and 21.21 X 0.60 = 12.726 mm. So something
very close to 19.05 + 1.08 = 20.13 mm or coming from the other direction
21.21 - 1.08 = 20.13 mm . Call a machinist to cut you something ... me I'll stick
with my dime shaper.

hank

 

[Patrick Johnson]

Patrick Johnson, Howdy;

So, basically what you imply is that if my tip is 12 mm, then I should be
looking for something between a penny (19.05 mm), and a nickle (21.21 mm)

If your tip is 12mm or larger, then a quarter, nickel or dime curvature will work well for you. You only need to choose "rounder" curvatures when your tip is smaller than 12mm (nickel or rounder for 11-12mm, penny or rounder for 10-11mm, dime or rounder for up to 10mm).

19.05 X 0.60 = 11.43 mm, and 21.21 X 0.60 = 12.726 mm. So something very close to 19.05 + 1.08 = 20.13 mm or coming from the other direction 21.21 - 1.08 = 20.13 mm.

The width of a 60-degree arc is 0.50 x the circle's diameter, not 0.60 - I rounded the results to even millimeters.

I'll stick with my dime shaper.

A dime shape works with just about any tip width, so you're good.

pj
chgo

 

[Patrick Johnson]

Isn't a dime radius a dime radius whether it's a 10mm or 14mm shaft? Brian.

LOL.

Don't make the pool scientist have to answer any difficult questions.

Here's an easy one for you (don't want to sprain anything): Did Brian's question make sense?

Take your time...

pj
chgo

 

[jrctherake]

PJ,

I agree that the smaller the tip, the closer to a dime shape is needed.

I carry most things to the extremes. Why should pool be any different? So, I use more than a dime eventhough, my shaft is 12.4.

Going by your chart a cue would have to be ~8 mm before it "needed" the shape I use.

I think the off center hits feel, sound and perform different (better) when the shape matches (or is even sharper) what you describe.

Most should've already known this but, for the people that didn't:

very good and straight to the point post,

Jeff

 

[Patrick Johnson]

PJ,

I agree that the smaller the tip, the closer to a dime shape is needed.

I carry most things to the extremes. Why should pool be any different? So, I use more than a dime eventhough, my shaft is 12.4.

Going by your chart a cue would have to be ~8 mm before it "needed" the shape I use.

I think the off center hits feel, sound and perform different (better) when the shape matches (or is even sharper) what you describe.

Most should've already known this but, for the people that didn't:

very good and straight to the point post,

Jeff

Thanks, Jeff.

Since a 60 degree arc's width is the same as the circle's radius, the general rule is that your tip's curvature radius should be smaller than your tip's width.

So an 8mm tip width needs a tip curvature radius of less than 8mm (less than 16mm diameter, a little smaller than a dime).

pj
chgo

 

[jviss]

Rounder?

This is an interesting and potentially useful post, Patrick, but there's one point of confusion (for me) I'd like to point out. You use the term "rounder" to mean "smaller radius." Circles of smaller radii are no more round than circles of larger radii, they are simply smaller radii! So, you should just ay that rather than use a term that is fundamentally incorrect, and potentially confusing.

In addition, per your observation that the chord of a 60º arc is equal to the circle's radius, I think the bottom line here is that you are saying the radius of curvature of the tip should equal the width of the tip. Isn't that so?

 

[Patrick Johnson]

This is an interesting and potentially useful post, Patrick, but there's one point of confusion (for me) I'd like to point out. You use the term "rounder" to mean "smaller radius." Circles of smaller radii are no more round than circles of larger radii, they are simply smaller radii! So, you should just ay that rather than use a term that is fundamentally incorrect, and potentially confusing.

It’s common shorthand for that idea - like “flatter” instead of “arc with a larger radius” or “width” instead of “chord”. I’m aiming to communicate rather than teach geometry terminology.

In addition, per your observation that the chord of a 60º arc is equal to the circle's radius, I think the bottom line here is that you are saying the radius of curvature of the tip should equal the width of the tip. Isn't that so?

As I said, “your tip’s curvature radius should be smaller than your tip’s width.” If it’s exactly the same size you’re hitting on the tip’s edge at maximum spin.

pj
chgo

 

[KissedOut]

Is there any research showing that a circular tip shape is optimal, as compared to an elongated curve? Some of the 3c tips I see the big boys use look like they aren't circular curves. But it is hard to tell.

 

[Patrick Johnson]

Is there any research showing that a circular tip shape is optimal, as compared to an elongated curve? Some of the 3c tips I see the big boys use look like they aren't circular curves. But it is hard to tell.

I've heard the theory that rounding the tip mostly at its edge and leaving its center more flat is more "forgiving" for centerball hits while still avoiding hitting on the edge when using maximum spin. Don't know how well it does either one.

pj
chgo