An 1892 glossary of bowling terms from a publication of
Spalding's Athletic Library
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The glossary mentions "all three balls", in contrast to modern ten-pin bowling in which two ball rolls are allowed in each frame.
Bowling ball core ("weight block") technical specifications include RG, differential of RG, intermediate differential, and (a)symmetry.
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Asymmetric balls have non-zero values of intermediate differential.
A
backup ball
delivery causes the ball to hook in a direction opposite that of a conventional delivery. Shown: left-handed delivery by Eric Jones hooks from right to left.
A ball's average
speed
can be estimated based on its time of travel over the sixty feet from the foul line to the headpin. Because of friction, a ball's speed decreases between release and reaching the pins.
In most two-handed deliveries, the last moment of the
release
involves only one hand. Since the thumb is never inserted, strong
axis rotation
and
hooking
can be achieved. Shown: Kyle Troup, 2022.
A custom-drilled ball with a
fingertip grip
; finger holes are relatively far from the thumb hole, compared to balls having a
conventional grip
.
The texture of ball surfaces—measured in "
grit
" of abrasives used—affects ball path (skid distance and hook intensity).
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Handicap
scoring:
Though the second bowler's
scratch
score 183 is higher than the first bowler's
scratch
score 181, the first bowler's higher
handicap
(58 vs. 53) causes his total 239 to exceed the second bowler's total 236.
The
hook
is the second of three phases
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of ball motion.
(Horizontal scale is compressed)
A ball's motion, especially its hook, is governed by several factors.
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Terms describing deviations from an ideal bowling ball path
Bowlers are said to be
matched up
when they optimize their
release ratio
—ratio of a ball's speed and
rev rate
at time of release—so that the ball achieves full traction immediately before contacting the pins to maximize the useful energy of impact.
Terms describing deviations from an ideal bowling ball path
The
pitch
(angle) at which thumb and finger holes are drilled−either forward or reverse—helps to regulate how a ball is released.
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Lateral pitch angles (perpendicular to this diagram) are also custom fit.
Conceptual illustration of
ball speed
and
rev rate
during the
skid
and
hook
phases, until they converge upon entering the
roll
phase. The
initial
ratio of ball speed to rev rate—the ratio at the time of
release
—is called the
release ratio
. Rev rate increases (motion of yellow arrowheads) until it matches the decreasing ball speed upon entering the roll phase.
The so-called "Rule of 31"—actually an informal guideline—calculates the approximate board on which a ball should exit a particular
oil pattern
based on the length of the pattern, in order to achieve a strike.
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Though bowling scores are generally linearly proportional to
strike
frequency, there is substantial variance based on whether the strikes are consecutive, and based on the number of open frames versus spares. In this dataset, such variance can approach 90 pins per set (30 pins per game), shown by the vertical extent of the shaded bar.
Attempts to convert the 4-5-7
split
(right-handed delivery using pearl coverstock bowling ball). Ball approaches at an angle to give the 4-pin enough forward momentum to contact the 7-pin. However, splitting the 4-5 gap too evenly sends the 4-pin sideways toward the gutter without contacting the 7-pin.
Conceptual diagram of a
sport pattern
(Horizontal scale is compressed)
Bowling ball core ("weight block") technical specifications include RG, differential of RG, intermediate differential, and (a)symmetry.
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Symmetric balls do not have values of intermediate differential.
Adjusting screws placed on the sides of these
circa
1895 bowling lanes design allow adjustment of lane
topography
.
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