Difference between revisions of "Extra hole"

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==Definition==
==Definition==  
 
[[Image:xhole.jpg|thumb|right|pxsize|Figure 1]]
 
Extra holes are used to fine tune reaction of a bowling ball.<br /><br />
 
  
*Extra holes are optional when considering a layout.
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A hole in the ball that is not used for gripping purposes and is not considered a vent hole.
*A maximum of 1 extra hole is allowed per ball
 
*Maximum diameter is 1 3/8" including [[bevel]]
 
*No limit to extra hole depth
 
*Small extra holes drilled deep have more of an effect on ball reaction than large shallow extra holes. This is due to the small deep hole taking out some of the [[core]] of the ball, this causing a change in [[differential]] and [[radius of gyration]].
 
  
Extra holes can fine tune a reaction based on the distance from positive axis point, [[midline]] and [[vertical axis line]] (VAL). Extra holes are usually placed on a line through the bowier's [[positive axis point]], horizontally that reference line is the midline, vertically that reference line is the [[vertial axis line]]. The effect of the extra hole is enhanced when placed on these reference lines. See figure 1 for details regarding the location of PAP, VAL and [[Midline]].
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==Purpose==
  
==Flare Increasing Extra Hole==
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Often referred to as balance holes, or weight holes, Extra holes were originally intended to keep the ball within static weight limits set by the USBC (then known as the ABC). This is no longer the case, though a ball with a extra MUST be within static weight limits.
[[Image:xhole2.jpg|thumb|right|Figure 2]]
 
A flare increasing extra hole is located past the positive axis point on a line parallel to the [[midline]] (Figure 2 numbered location 1).
 
This location of the extra hole offers and increase in mid-lane, backend reaction and [[flare]].
 
The further away the extra hole gets from the positive axis point at a limit of 3 3/8", the greater the influence on reaction.<br /><br />
 
Another location for a reaction enhancing extra hole is below the [[positive axis point]] (PAP) on the [[vertical axis line]](Figure 2 numbered location 2). Reaction is enhanced on this line in the midlane, but backend is diminished compared to the hole past the PAP on a line parallel to the midline. <br /><br /><br />
 
  
==Flare Decreasing Extra Hole==
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Extra holes are now an important part of the layout on a ball. According to Mr. Pinel, the extra holes account for up 84% of ball motion.
  
A flare decreasing extra hole is located on a line parallel to the midline before the positive axis point.
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With the help of Steven Freshour, Mo Pinel created the Gradient Line Balance Hole System, which allows us to place an extra hole in specific places on the ball and accurately predict what the final ball motion will be. Using the Gradient Line, we decrease ball dynamics by 29% (P1), or increase ball dynamics by up to 55% (P4).
Flare. midlane and backend reaction is dimished with this extra hole location (Figure 2 numbered location 3).<br /><br />Another location for a reaction reducing extra hole is above the positive axis point on the VAL (Figure 2 numbered location 4). An extra hole placed on this plane offers the least track flare, midlane and backend reaction. The further away the extra hole gets from the positive axis point at a limit of 3 3/8", the greater the influence on reaction.
 
  
[[User:Megamav|Megamav]] 23:22, 8 August 2007 (EDT)
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Extra holes have direct effect on the intermediate differential and total differential, which in turn affect the differential ratio of the final ball.
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==Articles==
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See: [[Gradient_Line_Balance_Hole|Gradient Line Balance Hole]] - by Mo Pinel<br />
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[[Category: Glossary]]

Latest revision as of 08:37, 5 January 2012

Definition

A hole in the ball that is not used for gripping purposes and is not considered a vent hole.

Purpose

Often referred to as balance holes, or weight holes, Extra holes were originally intended to keep the ball within static weight limits set by the USBC (then known as the ABC). This is no longer the case, though a ball with a extra MUST be within static weight limits.

Extra holes are now an important part of the layout on a ball. According to Mr. Pinel, the extra holes account for up 84% of ball motion.

With the help of Steven Freshour, Mo Pinel created the Gradient Line Balance Hole System, which allows us to place an extra hole in specific places on the ball and accurately predict what the final ball motion will be. Using the Gradient Line, we decrease ball dynamics by 29% (P1), or increase ball dynamics by up to 55% (P4).

Extra holes have direct effect on the intermediate differential and total differential, which in turn affect the differential ratio of the final ball.

Articles

See: Gradient Line Balance Hole - by Mo Pinel