Pin up, Low RG

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dlcohen
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Pin up, Low RG

Post by dlcohen »

I recently bought Storm Axion Pearl, low RG of 2.48 because I wanted it to rev up early. Yet, I had it drilled pin up, which seems to me to contradict the low RG. Taking out weight from top of weight block should increase RG. Does this just result in increasing RG somewhat? I just shot 300 with it (yeah, yeah, house shot), and like it, but it is bugging me as to why this makes sense...or not. Any thoughts? Thanks much.
dlcohen
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Re: Pin up, Low RG

Post by dlcohen »

Replying to myself...the info on what drilling will do to RG came from "Beyond Bowling: The Basics". However, Storm site has a post that refutes that:
When you remove mass from the top of the core, you are only removing mass from one side of it.
This changes the position of the center of gravity inside it.
Removing mass from the top forces the center of gravity down from where it originally was.
This makes the heaviest spot on the ball further away from the geometric center of the ball which raises the RG.
Since the top of the weight block is always closer to the surface, you’re always going to have more effect when drilling into the top.
See this:
https://news.stormbowling.com/2017/05/1 ... -pin-down/
So, would like to here from someone who might clear this up?
44boyd
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Re: Pin up, Low RG

Post by 44boyd »

This is why I like Radical, they give you the numbers after drilling. Wish others would follow.
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EricHartwell
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Re: Pin up, Low RG

Post by EricHartwell »

dlcohen wrote: August 4th, 2021, 11:40 pm Replying to myself...the info on what drilling will do to RG came from "Beyond Bowling: The Basics". However, Storm site has a post that refutes that:
When you remove mass from the top of the core, you are only removing mass from one side of it.
This changes the position of the center of gravity inside it.
Removing mass from the top forces the center of gravity down from where it originally was.
This makes the heaviest spot on the ball further away from the geometric center of the ball which raises the RG.
Since the top of the weight block is always closer to the surface, you’re always going to have more effect when drilling into the top.
See this:
https://news.stormbowling.com/2017/05/1 ... -pin-down/
So, would like to here from someone who might clear this up?
It is not about the Cg location.
It is about the Shape of the core and the new Rg contours created post drilling.
Drill the holes to the 4 1/2" limit, it will make a difference.

Drilling into the Top of the core lowers the differential. Less flare
Drilling into the Side of the core Raises the differential. More flare

Drilling a ball with Long Pin to PAP (pin distances 5" to 6") is a High Rg drilling for -that- ball.
Short Pin to PAP drillings (Pin distances 1"to 3") is a Low Rg drilling for -that- ball.
Eric Hartwell

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300Bowler
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Re: Pin up, Low RG

Post by 300Bowler »

Don't worry about RG. Pay attention to differential. Differentials are what matter. pin up(low Val angle) increases diff and pin down decreases diff.
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