-
Axis Tilt
-
The vertical angle
between the axis of
rotation and the surface
of the lane.
-
Axis Rotation
-
The angle between the
axis of rotation and the
direction in which the
bowling ball is
traveling.
-
Balance Hole
-
A
hole drilled into a
bowling ball to alter
either the static or
dynamic mass
distribution in a
bowling ball. A ball
driller can use this
type of hole to make a
bowling ball comply with
USBC specifications
and/or to alter the ball
dynamics to either
increase or decrease
hook characteristics.
-
Breakpoint
-
The point on the lane
where the ball has its
strongest change in
direction.
-
Center Line
-
A
vertical line that
extends from the center
of the thumb hole
through the point
between the finger
holes.
-
Center of Gravity (CG)
-
The marking on the
surface of the bowling
ball about which the
weight of the bowling
ball is equally
distributed in any
direction. The true
center of gravity of the
bowling ball will be
somewhere between this
mark and the center of
the ball.
-
Flare
-
The migration of the
ball's spin axis. This
is created by a
combination of the
layout of the ball and
the dynamics of the core
of the ball.
-
Hook Potential
-
A
scale used describe the
total amount of hook
possible from a bowling
ball. The amount of hook
a bowler will obtain
with any given bowling
ball will depend on the
layout used and the
bowler's delivery
dynamics.
-
Intermediate
Differential
-
The difference between
the radius of gyration
of the y-axis of the
ball and the z-axis.
Bowling balls with
asymmetric cores will
have a larger
intermediate
differential than balls
with symmetric cores.
-
Leveraged
-
A
term indicating that the
pin is 3 3/8 inches from
the PAP.
-
Loft
-
The distance from the
foul line that the ball
impacts the lane.
-
Mass Bias
-
A
modification of the core
that places the mass of
the core away from the
x-axis of the ball. The
mass bias of a bowling
ball is not always in
the same location as the
preferred spin axis.
-
Mid-Line
-
A
horizontal line that
crosses through the
center of the grip.
-
Pin (on a bowling ball)
-
The marking on the
surface of the ball that
indicates the location
of the top of the core.
-
Pitch
-
The angle at which a
hole is drilled into a
bowling ball.
-
Plasticizer
-
Any of various
substances added to
plastics or other
materials to make or
keep them soft or
pliable.
-
Positive Axis Point
(PAP)
-
The point on the
opposite side of the
track that marks the
axis about which the
ball is spinning at the
point of release.
-
Radius of Gyration (RG)
-
The distance from the
axis of rotation at
which one could
concentrate the total
mass of the bowling ball
without changing its
rotational properties.
The current USBC limits
are 2.43 to 2.80.
-
Span
-
The distance between the
inside edges of the
gripping holes.
-
Track
-
The surface of the ball
that comes into contact
with the lane. The track
can be found by looking
for the oil rings on the
ball.
-
Velocity
-
The speed and direction
of the bowling ball.
-
Vertical Axis Line
-
A
line perpendicular to
the mid-line that
crosses through the
positive axis point.
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