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Technical Terms
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Actual
span - Distance from edge of thumb hole
nearest to center, to edge of finger holes nearest
to center, including all inserts and/or grips.
Angle of entry –
Angle, measured parallel to the boards, at which
the bowling ball hits the pocket after completing
it’s path down the lane.
Arc – Ball
path from foul line to headpin that does not have
a sharp, defined break point.
Axis of rotation
– Imaginary line, perpendicular to the track,
along which a bowling ball rotates around during
it’s path down the lane.
Axis point –
One of two points located on opposite poles marking
the endpoints of the axis of rotation.
Axis tilt –
Angle between axis of rotation and the horizontal
plane – caused by the bowler at the release,
represents an angle of the axis of rotation above
a horizontal line through the middle of the ball.
Axis rotation
– The degree that the bowler’s axis
of rotated in the horizontal plane towards the
bowler at release.
Axis weight –
Method of drilling in which the weight block is
positioned so that it’s mass is evenly distributed
around the axis of rotation. (aka: pin on the
PAP)
Back of hole –
Portion of hole facing away from the center of
the grip.
Backend – Fifteen
feet of lane directly preceding the headpin.
Backup ball –
Style of bowling in which the movement of the
ball is from left to right for right-handers and
from right to left for left-handers.
Balance hole –
A hole placed in the ball to bring a ball back
into ABC static balance specifications.
Ball reaction –
Change in direction of the ball’s path as
it travels from foul line to pins.
Bevel – Rounded
edge of any hole drilled in a bowling ball.
Boards – Any
one of 39 individual strips of wood pieced together
to comprise the surface of the lane.
Bottom weight –
Imbalance in which the half of the ball opposite
the center of the grip weighs more than the half
containing the center of the grip.
Break point – Point in the trajectory
of a bowling ball at which the ball makes it’s
greatest change in direction.
Bridge – Distance
between the finger holes.
Caliper – A
graduated rule with one sliding jaw and one that
is stationary. Used to determine thumb oval sizes.
Callus – Thickened,
hardened area of skin caused by build-up due to
friction against the skin.
Carry down –
Oil moved down the lane by the bowling ball.
Center of gravity (CG)
– That point in a body or system around
which the whole mass is concentrated and may be
assumed to act. The point on the surface of the
bowling ball where static balance is zero in all
directions on a do-do scale – usually marked
by a logo.
Center line –
Vertical line between the fingers and through
the middle of the thumb.
Center line transposition
(CLT) – Lateral
shift of the center line, after drilling thumb
first.
Conventional grip
– Grip in which the bowler places his/her
fingers in the ball to the second joint at a 90
degree angle, while placing his/her entire thumb
in the ball.
Cosmetic bevel –
Bevel at the extreme top of the hole which provides
a neat appearance to the finished hole.
Coverstock –
Outer shell of the bowling ball (composition varies;
polyester, urethane, reactive resin, particle
reactive resin)
Cranker – Bowler
who generates revolutions by a cupped wrist, bent
elbow or muscled armswing.
Cut to Cut span –
Distance from edge of thumb hole nearest to center,
to edge of finger holes nearest to center, excluding
all inserts and/or grips.
Deflection –
Amount of displacement incurred in a bowling ball’s
trajectory after making contact with a headpin.
Degree of oval –
Degree of oval of a hole will be to the center
line measured on a horizontal line from the center
of the thumb hole.
Differential RG –
Difference between the low RG and high RG values
of any bowling ball.
Dropped ring finger
– A fit in which the ring finger span is
intentionally shortened to be less than the middle
finger span.
Dull finish –
Referring to the bowling balls surface texture
caused by using sandpaper and/or scotch brite
pads.
Durometer – Device used to measur the hardness
of a bowling ball.
Dynamic imbalance – Measure of weight in
an object in motion.
Dynamics – Characteristics of the mass inside
of a bowling ball.
Equator – Line around the ball, perpendicular
to the vertical axis and the midline covering
the entire circumference of the ball.
Finger weight – Imbalance which effectively
makes the side of the ball, divided by the midline,
containing the finger holes, heavier than the
side containing the thumb hole.
Flare – Refers to the bowling ball changing
it’s axis of rotation while seeking it’s
preferred spin axis during it’s path down
the lane. The result is several distinct oil rings
being visible around the ball.
Forward pitch – The drilled hole, either
finger or thumb, is angled towards the midline
of the grip.
Friction – The resistance to motion of two
moving objects or surfaces that touch.
Front of hole – Portion of the hole facing
toward the center of grip.
Full roller – A bowler whose track passes
between the thumb and fingers and whose track
measures the circumference of the ball.
Full span – Distance from edge of thumb
hole nearest to center to edge of finger holes
nearest to center, including all inserts and grips.
Gripper/Squeezer – Someone who holds on
to the ball with excessive force or muscle.
Heads – Portion of the lane from the foul
line to the range finders (arrows) which are generally
located 15 to 18 feet down the lane.
High performance balls – Bowling balls designed
to produce specific reactions for different bowlers.
High track – A track outside of the thumb
hole and finger holes that is no more than an
inch from either.
Hinge angle – Angle at which the thumb is
connected to the hand.
Hit the ball – Acceleration of the hand
around the ball, from bottom to side, at the release
point.
Hook – Amount, measured in boards and angle,
that a bowling ball deviates from it’s original
trajectory in it’s path down the lane.
Hook angle – Angle at which the bowling
ball changes direction at it’s break point.
Hook potential – Degree to which the properties
designed into a bowling ball and in it’s
potential to traverse towards during it’s
path down the lane.
Horizontal axis measurement – Displacement
of the center of gravity from the geometric center
of a bowling ball.
Imbalance – Displacement of the center of
gravity from the geometric center of a bowling
ball.
Inside line – The portion of the lane bounded
by ten boards on each side.
Label shift – Displacement of the label
from the center of the grip.
Lateral pitches – Right and left components
of hole angle in any drilled bowling ball.
Leverage position – In bowling, it is the
position at which the bowler is able to use his
body to create rotation, speed and momentum on
the bowling ball (balanced position).
Leverage weight – A drilling in which the
center of the weight block is placed at a 45 degree
angle to the axis of rotation of the bowler.
Line – Intended path of the ball down the
lane.
Loft – Distance the ball travels before
actually making contact with the lane surface
after the bowler releases the bowling ball.
Low track – A track outside the finger holes
and thumb hole, but more than two inches from
either.
Mark – Point on the lane at which the bowler
is aiming.
Mass bias – Weight in a particular area
of the ball.
Midline – Line that perpendicularly bisects
the center line of the grip. A horizontal line
halfway between the fingers and thumb.
Moment of inertia – Amount of force required
to spin an object.
Negative weight – Imbalance which causes
thumb, negative side or bottom weight.
Negative side weight – Imbalance in a ball
that effectively makes the left side of the ball
heavier for right handed release players, and
the right side of the ball heavier for left handed
release players.
Ovaled hole – The shape of a hole being
out of round.
Pin – A small round colored pin in a bowling
ball that signifies the top of the core/weight
block. Usually colored the same as the engraving
paint.
Pin action – The manner in which the pins
react to the impact of the bowling ball.
Pin shift – The process of creating reaction
in a bowling ball by displacing the pin from the
axis of rotation or the PAP.
Pitch – The angle at which a hole is drilled
into a bowling ball in relationship to the center
of the ball.
Pivot point – Point on the ball’s
surface where all track lines intersect.
Positive axis point (PAP) – Point on the
surface of the ball that signifies the bowlers
axis of rotation, on the positive side of the
ball.
Positive weight – Imbalance which causes
finger, positive side or top weight.
Positive side weight – Imbalance that effectively
makes the right side of the bowling ball from
the center of grip heavier than the left for right
handed release players, and left side of the ball
heavier than the right for left handed release
players.
Preferred spin axis (PSA) – The axis about which
the bowling ball wants to rotate around.
Ðàäèóñ Ãèðàöèè (RG) (RG) – An account/measurement
of the distribution of the mass in an object from
the geometric center.
Release point – Point in the delivery at
which the ball leaves the hand.
Reverse pitch – The drilled hole, either
finger or thumb, is angled away from the midline
(center) of the grip.
Reverse block – A lane condition in which
the inside portion of the lane is covered with
less conditioner than the outside.
Revolutions – The number of times the bowling
ball makes a complete rotation about its axis
during its path down the lane.
Safe zone – The area on the ball from one
inch inside the vertical axis line to a line from
the bowlers PAP to the ring finger and from the
PAP to the equator, in which the pin of a ball
can be placed safely without the track and holes
interfering with one another.
Shell – The outer portion of a bowling ball
surrounding the core.
Shiny – A ball that looks glossy. In general,
shiny balls are smoother textured.
Skid – The portion of the bowling balls
path in which the velocity of the contact point
on the ball is greater than zero and the ball
is therefore actually not rolling but is instead
sliding down the lane.
Snap – A ball path which has a sharp, defined
breakpoint. However, when referring to the actual
break point, the term snap is often used as a
quantifying term.
Span – Distance from edge of thumb hole
nearest to the center, to the edge of finger holes
nearest to the center.
Squirt – The action of a bowling ball as
it hydroplanes past its breakpoint.
Stacked leverage – A layout where the pin
and CG are the same distance from the bowler’s
PAP.
Static weights – Measurements of forces
at work in systems that are at rest. Side, finger
and top weights measured on a do-do scale.
Stroker – Someone who has a smooth swing
and delivery without sudden acceleratioin
Surface – The texture, both finish and hardness,
of a bowling ball.
Tapered – Any hole in which the upper diameter
of the hole is larger than the bottom.
Thumb weight – An imbalance in a bowling
ball which effectively makes the half of the ball
containing the thumb heavier than the half containing
the fingers, separated by the midline.
Track – Area of the bowling ball that makes
contact with the lane surface during its path
down the lane. Because of revolving motion, this
area is usually in the form of a ring or rings
around the ball.
Track flare – The result of the migration
of a bowling ball from the bowler’s axis
of rotation to the ball’s preferred spin
axis.
Track flare management – The regulation
of the position of the flare intersections and
thus the amount of flare.
Traction – The power, as of tires on pavement,
to grip or hold to a surface while moving without
slipping.
Vertical axis line/Midplane – A line perpendicular
to the midline that passes through the bowler’s
positive axis point and the negative axis point
when extended completely around the ball. Separates
top of ball from bottom of ball on the bowler’s
axis of rotation.
Vertical axis measurement – The perpendicular
measurement from the midline to the bowler’s
PAP.
Weight block – Traditionally, the dense
part of material found in the interior of a bowling
ball designed to help create ball reaction.
Weight hole – Same as balance hole
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