Information on the 3 Piece Core
The 3-piece, full-size core has been an
industry staple throughout bowling's history. The original core
construction of a bowling ball was a single density sphere. Technology
evolved and a weight mass was placed inside the upper edge of the core
to counterbalance the weight that is removed from the top half of the
ball during the drilling process, creating top weight. Although there
is not a limit on top weight in an un-drilled ball, the USBC restricts
the amount of top or bottom weight in a drilled ball to 3 ounces.
Ebonite's upper limit on top weight in an un-drilled ball is five
ounces and lower limit is one and one-half ounces. The upper limit on
lighter weight balls is on a descending sliding scale to reflect the
density differences on the core weight. This ensures that the drilled
ball will be within USBC specifications for top/bottom weight.
A higher density polyester compound is poured
into the core mold and is allowed to harden before the lower density
material, which makes up the rest of the core, is added. This high
density weight mass has the same round contour as the core on one side
and is flat on the other side. Appropriately, the name "pancake" has
been assigned to this weight mass. Bowlers found a stronger hook
potential when the pancake was introduced to the core construction. The
amount of top weight in an un-drilled ball can be altered by varying
the density of the pancake material or by increasing its thickness.
Higher top weight creates a ball reaction that goes further down the
lane and has a stronger backend hook. Lower top weight causes an
earlier breakpoint and a smoother hook pattern. The center of the top
weight is signified by a mark called the center of gravity. It is
called "CG" for short.
Moving the CG above the center of span, towards
the fingers, creates finger weight. This increases the skid
characteristics of the ball. Moving the CG below the center of span,
towards the thumb, creates thumb weight. This causes an earlier
breakpoint. Moving the CG to the right of the center of span (to the
left of the span for left-handers) creates positive side weight. This
increases the overall hook. And moving the CG to the left of the span
(to the right of the span for left-handers) creates negative side
weight. This reduces the amount of hook. The USBC limit on finger,
thumb, positive, or negative weights is 1 ounce.
The 3-piece, full size core is higher in RG and
low in RG Differential. The higher RG creates a delayed breakpoint. The
low RG differential results in an easy to control, lower hook
potential. The 3-piece core is best for drier lanes, slow ball speeds,
and those who like to play a straighter line to the pocket.
Choosing the proper ball construction and
surface texture for your bowling style and lane condition will be the
most important decision you and your pro shop operator will make.
Choosing a drilling layout will alter the ball's characteristics within
its performance parameters to fine-tune the overall reaction. Drilling
layouts will not produce ball reaction without proper mechanics from
the bowler and proper surface texture.