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, measure parallel to the boards, at which the bowling ball hits the pocket after completing its path down the lane.

Approach

The area at least 15' long, on which the player walks to the foul line. Usually adjacent to the ball returns and has spots embedded in the approach to aid in lining up.

Arc

Describes a ball path from foul line to headpin that does not have a sharp, defined break point.

Axis leverage

Type of drilling in which the label of center of gravity is placed on the positive axis and the pin is positioned between the positive axis point and the center of grip, usually above the line to the ring finger.

Axis of rotation

(example, 0, 45, and 90 degrees) This is a measure of the direction of the initial rotation on the ball with respect to the lane. It is a measurement of the angle between the initial spin axis and the foul line running across the lane. A zero degree axis of rotation is all forward roll. The rotation on the ball is in the direction of the forward travel. The rotation will help keep the ball in the initial direction. The ball will not hook very much. It will roll out early. Therefore, a bowler with this style will need balls drilled to go long. A 90-degree axis of rotation is all side roll. The rotation is perpendicular to the initial direction. The rotation is trying to make the ball hook at a 90-degree angle to the initial direction. This gives the ball more potential to hook. This style causes the ball to skid further down the lane and then hook more. A bowler with this style will most likely need balls drilled to hook earlier; such as, axis weight or pins closer to their axis.

Axis point

One of two points located on opposite poles marking the endpoints of the axis of rotation.

Axis rotation

Angle between the Translational and rotational energy vectors. The Degree the axis is rotated on the horizontal axis.

Axis tilt

This is the angle of rotation put on the ball by the bowler. The rotational positioning of the ball is critical to creating the potential for hook.

The wider the angle between the rotational axis and the forward path of the ball, the greater potential for hook. If the angle is zero, then no hook will occur.

Axis weight

Type of drilling in which the weight block is positioned such that its mass is evenly distributed about the axis of rotation. AKA- Pin on the axis.

Back to the Top

Portion of bowler's delivery from the time the ball breaks the lateral plain of the body until the ball reaches the apex of the bowler's swing.

Backend

The 15 ft. 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

An extra hole drilled in a specific position in the bowling ball. This hole is used to balance the ball statically and alter the overall reaction of the ball.

Ball plug

A two part epoxy used to fill holes in bowling balls.

Ball spinner

Motorized cup and pulley system used to spin a bowling ball during sanding or polishing.

Bevel

Refers to the rounded edge of any hole drilled into a bowling ball.

Bevel knife (Three edged knife)

A knife with three edges used to customize hole size and bevel.

Boards

Any one of 39 one inch wide individual pieces 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

The portion of the lane where the bowling ball completes its transition from skid to traction and provides the greatest amount of hook. This generally occurs in the last 20 feet of the lane.

Bridge

Distance between the finger holes. A common place for ball cracks to occur.

Back to the Top

Oil moved down the lane by the passing of bowling balls.

Center of gravity

1) The point, at which, no matter how the ball is rotated, it will weigh the same. 2) It is the point at which the entire mass of a bowling ball acts as if it is concentrated. 3) The point on the surface of the bowling ball where static balance is zero for both finger and side weights; usually marked by a logo.

Centerline

The vertical line between the fingers and through the middle of the thumb.

Centerline transposition (CLT)

A lateral shift of the centerline after drilling thumb to drill fingers off of.

Channel

There are 2 channels on each side of the lane. Once a ball falls into the channel or gutter before hitting pins, the bowler shall receive a zero.

Conventional grip

A grip in which the bowler places his or her fingers in the ball to the second joint at a 90 angle, while placing his or her entire thumb in the ball.

Core

Internal portion of bowling ball around which the shell is poured.

Core axis angle

Angle that which the core is from the bowlers axis point.

Contour Abrasion Blocks

A concave tool contoured to the shape of the bowling ball, used to aid in the sanding and finishing process to maintain the true roundness of the bowling ball.

Count

The number of pins knocked down on the first ball.

Cranker

A bowler who generates revolutions by a cupped, broken or muscled armswing.

Cut span/ 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. See also Edge Span/Edge to Edge Span.

Back to the Top

Amount of displacement incurred in a bowling ball's trajectory after making contact with a headpin.

Degree of oval

The degree from centerline the oval of a hole will be.

Dodo scale

A balance beam scale system that measures weight and distance. Used to find whether a bowling ball will meet ABC/WIBC guidelines of imbalance for one side to another.

Differential (of Radius of Gyration)

The difference of the radius of gyration of a bowling ball’s X axis (the weight block vertical) compared to the radius of gyration of the same ball’s Y or Z axis (the weight block horizontal). Differential is an indicator of a bowling ball’s track flare potential. Bowling balls with lower differentials are more stable, therefore generating less track flare potential. Bowling balls with higher differentials are unstable, therefore generating a much larger track flare potential. Also, differential is a guide to the internal versatility of a ball. It can indicate just how much of a length adjustment can be made through drilling. Balls with lower differential will allow only modest length adjustments whereas balls with higher differential may translate into a length window of up to 5-times that of low differential balls.

Drill jig

A device used to hold a bowling ball stationary, while being drilled. A jig can be either stationary and used on a mill press or have sliding plates to adjust for desired pitch.

Dull

Refers to the surface of a bowling ball appearing listless. In general a dull bowling ball is one in which the pours are open and clean.

Durometer

Device used to measure the hardness of a bowling ball.

Dynamic imbalance

Measure of weight in an object in motion.

Dynamics

The characteristics of the mass inside a bowling ball. This includes Moment of Inertia and Differential of Rg, which in turn contribute to the balls preferred spin axis.

Back to the Top

Distance from edge of thumb hole nearest to center to edge of finger holes nearest to center, excluding all inserts and/or grips.

Equator

The line around the ball perpendicular to the Midplane and the Midline covering the entire circumference of the ball.

Back to the Top

A grip in which the bowler inserts fingers to the first joint, with the combined total of angle of the two joint equals 90 , while placing the entire thumb in 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.

Flare

Refers to the bowling ball changing its axis of rotation during its path down the lane. The result is several different oil rings being visible around the ball.

Follow through

Portion of bowler's delivery after the ball has been released.

Forward pitch

The drilled hole, either finger or thumb, is angled towards the midline of the grip.

Foul

Touching or going beyond the foul line. When a bowler fouls they recieve zero count for that delivery.

Frame

One-tenth of a game. Each square on score sheet is one frame.

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/or grips. See also True Span, Actual Span.

Back to the Top

Someone who holds on to the ball with excessive force.

Gutter

There are 2 channels, one on each side of the lane. Once a ball falls into the channel or gutter before hitting pins, the bowler shall receive a zero.

Gutter ball-

Delivery which rolls off the lane and into the gutter. Once a ball falls into the channel or gutter before hitting pins, the bowler shall receive a zero.

Back to the Top

Portion of the lane from the foul line to the range finders which are generally located 15 to 18 feet down the lane.

Heavy hit

Refers to a pocket shot that makes more contact with the headpin than an ideal shot.

High performance balls

Premium balls designed to create specific reactions for different bowlers.

High track

Refers to 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

Refers to the acceleration of the hand, at the release point.

Hook

Refers to the amount, measured in boards and angle, that a bowling ball deviates from its original trajectory during its path down the lane.

Hook angle

Refers to the angle at which the bowling ball changes direction at its break point.

Hook potential

Refers to the capability a bowling ball has for traversing boards during its path down the lane.

Horizontal axis measurement

Is the distance, measured perpendicular to the centerline of the grip, at which the positive axis point is located.

Back to the Top

Is the displacement of the center of gravity from the geometric center of a bowling ball.

Inside

Refers to the portion of the lane bounded by ten boards on both sides.

Back to the Top

Refers to the displacement of the label from the center of the grip.

Layout tool

A tool used to draw the lines necessary to position the holes in the proper place upon a bowling ball.

Lateral pitches

Refer to the right and left components of pitch in any drilled hole in a bowling ball.

Leave

Refer to the pins remaining after the first delivery.

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.

Leverage weight

Refers to a drilling in which the center of the weight block is placed at a 45 degree angle with the axis of rotation.

Lift

Refers to the vertical component of a bowler's release.

Line

Refers to the intended path of the ball down the lane.

Linear velocity

Ball traveling down the lane towards the pins. See also Translational energy.

Loft

Is how far the ball travels before actually making contact with the lane surface.

Low track

A track outside the finger holes and thumb hole, but more than two inches from either.

Back to the Top

Point on the lane at which the bowler is aiming.

Mass bias

The position in a bowling ball, other than the pin where the mass is closest to the outside circumference of the ball.

Mid-line

Line that perpendicularly bisects the center line of the grip. A horizontal line halfway between the fingers and thumb.

Mid-plane

A line perpendicular to the midline that passes through the bowlers 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.

Mid or half weights

A ball whose net weight is more than .35 or below .8 of an integral weight.

Moment of inertia

The amount of force required to spin an object.

Back to the Top

Any imbalance, thumb, negative, or bottom.

Negative side weight

Imbalance in a ball that effectively makes the left side of the ball side heavier, for right handed release players, and right side of the ball heavier for left handed release players.

Back to the Top

Difference in span between middle and ring fingers.

Offset thumb

Outdated shift of thumb increasing ring finger span.

Oil Patterns

The way oil is distributed onto the lane. Here are the most common used in bowling centers. Top Hat – Heavy oil in the middle and very light on the outside. Christmas Tree – More oil in the middle than the outside. Tapered to the outside throughout the entire pattern. Sport – Permits ratio of 2:1 oil from inside to outside portion of the lane. Used on PBA and PWBA tours. Flat – Same amount of oil applied across the entire lane. Reverse Block – More oil applied to the outside boards than in the inside.

Open

To open is to rotate part of one's body in such a way pointed on a line away from the center of the lane.

Ovaled

Refers to the shape of a hole being obtuse.

Over reaction

Refers to a ball whose hook/oil ratio is very elastic. An over response of the balls contact or lack of contact to the surface of the lane.

Over turning the ball

Occurs when the bowler completes the entire rotation of the hand before releasing the ball.

Back to the Top

Particle

Relates to coverstocks, particle technology consists of small units of various materials added to the shell. Particle coverstocks provide increased traction in the oil.

Pin-In

The weight block is perfectly centered in the bowling ball. Pin-in balls will flare less than pin-out balls due to this factor.

Pin-Out

Generally, any ball with the pin two inches or more from the CG is considered a pin-out.

To create pin-out balls the weight block is not perfectly centered in the ball and this offsetting of the weight block tilts mass to one side of the ball creating a center of gravity away from the pin.

Pin-out balls induce roll since they will flare more by placing the pin in an unstable axis area for greater dynamics.

Pin-out balls often give the ball driller more latitude and drilling choices than pin in balls.

Pin

A small round discoloration on a bowling ball that marks the top of the weight block.

Pin action

Is the manner in which the pins react to the collision of the bowling ball.

Pin shift

Refers to the process of creating reaction in a bowling ball by displacing the pin from the Axis of rotation or the PAP.

Pitch

Refers to the angle at which a hole is drilled into a bowling ball.

Pitch gauge

A tool used to measure how much a hole is angled away from the center of the of the bowling ball.

Plug dams

Foam, neoprene, clay or plastic accessory used to coral excess plug to a desired height above the ball.

Plug pumps

An accessory used to obtain a predetermined amount of ball plug at the proper ratio.

Plug colors

Liquid coloring used to match plug to the bowling being plugged.

Pocket

Area between 1-2 pins for a lefty and 1-3 pins for a right hander.

Pocket Entry Angel

The angle at which the ball enters the pocket.

Positive Axis Point (PAP)

Point on the surface of the ball that is the end of the bowlers axis of rotation, on the positive side of the ball.

Positive weights

Any imbalance, finger, side or top.

Positive side weight

Imbalance that effectively makes the Right side of the bowling ball form the center of grip heavier than the left for right handed release player, and left side of the ball heavier than the right for left handed release player.

Power player

Someone who relies more on speed and revolutions than accuracy.

Preferred spin axis/preferential spin axis

Refers to the axis about which the bowling ball wants to rotate.

Pull the ball

Is when the bowler misses his or her target to the inside of the armswings intended direction.

Push away

Portion of delivery in which the bowler sets the ball in motion.

Back to the Top

An account of the distribution, of the mass in an object.

Relaxed finger tip

A finger tip grip in which stress on the joints has been reduced to prevent injury.

Release point

Point in the delivery at which the ball loses contact with the hand.

Reverse pitch

Pitch in which the center line of the hole is angled away from the 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.

RG

An account of the location of the mass in an object.

• High RG - High RG balls are those whose mass is displaced further from the center of the ball. These balls have a tendency to skid down the lane further and have a delayed breakpoint. Better for drier lane conditions or conditions needing strong,late hook.
• Low RG - Low RG balls are those with mass displaced closer to the center of the ball. These balls have a tendency to roll earlier and have a more predictable,smoother hook style. Better for more oiler lane conditions since the ball wants to hook sooner

 Router

A motorized tool with a blade raised off the surface or placed below the surface. Used to either remove excess material from outer surface of ball (i.e. Excess plugging material) or when modified used to make holes larger or custom sized.

Rotational energy

Spin or Revolutions put on the ball by the bowler. See also Angular Velocity.

Back to the Top

The area on the ball from one inch inside the midplane 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.

Sand paper

120,180,220,320,400,600,100,1500- Paper used to sand bowling balls to desired texture.

Scotch-Brite

This is an abrasive that is used to scuff or sand the ball surface to create different ball reactions or used to resurface the ball cover after the wear and tear from use. We recommend these 3 types of grits. 1. Burgundy – this is the roughest and equates to 240-grit sandpaper. 2. Green – this is the medium textured pad and it will produce a 500-600 grit finish. 3. Grey – this is the smoothest and finest grit pad. Will adjust the surface to an 800 finish.

Semi tip

Refers to a grip in which the bowler places his or her fingers in the ball between the first and second joint while placing the entire thumb in the ball.

Shell

Refers to the outer portion of a bowling ball surrounding the core.

Shiny

Refers to a ball that looks glossy. In general, shiny balls have fewer open/exposed pours.

Skid

Refers to the portion of the bowling ball's 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

Refers to a ball path that does have 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 center to edge of finger holes nearest to center.

Span gauge

A tool used to measure the actual distance between two holes drilled into a bowling ball.

Spare

Knocking down all remaining pins in the second ball or delivery.

Spindle sanders (bevel sander)

A motorized shaft and cutting tool, used to sand holes.

Split

Squirt

Refers to the action of a bowling ball as it hydroplanes past its breakpoint.

Static weights

Measurements of forces at work in systems that are at rest. Side, finger and top.

Stretched fingertip

A fingertip grip which puts excessive force on the joints and muscles of the hand. A greater than 90 total joint angles into the hole.

Strike

Knocking down all ten pins with the first ball or delivery.

Stroker

Someone who has smooth swing and delivery without sudden acceleration.

Surface

Refers to the texture, both shine and hardness, of a bowling ball.

Back to the Top

Refers to any hole in which the upper diameter of the hole is larger than the bottom.

Target

Where on the bowling lane the bowler is looking to place the ball.

Target Arrows

Sighting targets embedded in the lane to help the player align start position. Usually 15' down the lane from the foul line.

Three Piece Construction

A bowling ball constructed of three elements: the coverstock, the filler material and the high-density puck.

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.

Top Weight

This is the variation of the core height in a bowling ball. A core shifted up higher in a bowling ball creates higher top weight.The higher the top weight,the higher the RG of that ball.

Track

Area of bowling ball that makes contact with the 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

This is defined as axis migration. Flare is seen on a bowling ball as the side-by-side rings that occur as the ball spins down the lane and later rolls down the lane. This is due to the ball changing its axis of rotation while seeking its preferred spin axis.

Track flare has two main functions being first of all it is to orient the core to a more inertial position,(meaning resistance to change in rotation) and to provide the ball with an oil free surface area so that when the ball hits the dry part of the lane the friction is at its maximun potential. Track flare size is dependent on the amount of revolutions the bowler has,where the ball is drilled,what type of RG it has,the amount of differential RG and how much friction is present.

Starting with zero track flare,as flare is increased the increase in reaction starts at the backend and the more the flare is increased the more the increase in reaction moves toward the bowler.

The more track flare the earlier the ball hooks and less track flare creates better length and later hook.

Track flare management

The concept of regulating the position of the flare intersections and the amount of flare.

Translational energy

Ball traveling down the lane towards the pins. See also Linear Velocity.

True Positive Axis Point (True PAP)

The axis point for a bowler taken from a minimum track fare potential ball.

True span

Distance from edge of thumb hole nearest to center to edge of finger holes nearest to center, including all inserts and/or grips. See also Full Span, Actual Span.

Turn

The hand actions lateral movement at the release point.

Tweener

A player that has more accuracy and less power than a cranker, with more power than a straight player; also "stroker".

Back to the Top

An under response of the ball not reacting violently to changes in the amount of oil present.

Back to the Top

The perpendicular measurement from the midline to the bowlers PAP.

Back to the Top

Traditionally, it is the dense part (s) of material found in the interior of a bowling ball.

Weight hole

A non-grip hole that is used to achieve a specific imbalance.

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