Dual Angle Ball Layout

Bowlers Reference

Dual Angle Ball Layout Technique

Developing an Understanding

This discussion is not intended to make you an expert ball driller. The objective is to enhance your understanding of ball layout considerations and more effectively communicate with your ball driller. A second objective is to enhance your ability to make better choices as you create an arsenal of equipment that best matches your bowling style and lane conditions.

Dual Angle Layout

When a bowler purchases a high performance ball, it is only the first step. If the ball is to perform as expected, the pro shop measures the bowler's hand to match the bowler's physical characteristics and capabilities. Equally important, the technician fits the ball to the bowler's hand and accurately tailors where the gripping holes are placed on the ball in order to match bowler's style with the expected lane conditions. An effective ball layout includes an accurate analysis and matching of the ball physics, the lane conditions, the bowler's style, and the intended ball reaction. Each bowler and ball is unique, and if the end result is to be effective, the fitting and the ball layout is important.

It is the bowler's responsibility to provide accurate information and data. The pro shop technician relies on data that accurately matches the ball to the bowler's style and objectives. The driller interprets bowler-supplied data and the driller's understanding to determine an appropriate ball layout. We have covered hand fitting techniques in other discussions, and now it is time to use this information and data. While there are a variety of ball layout methodologies, the most accurate method is through the use of a technique called the Dual Angle Layout Technique.

The Dual Angle Layout Technique is based on the physics of the ball and the bowler's style and objectives. In this discussion, our objective is to provide an understanding of how layouts affect your equipment. Since our focus is on the layout of the ball, it is first assumed hand fitting task is known, as well as the bowler unique Positive Axis Point (PAP) measurements. If not, you are encouraged to review the Fitting section of this document. Also assumed is an understanding of ball motion as it moves down the lane in a Skid, transitions from the Skid into a turn or Hook, and finally Rolls into the Pins.

The Dual Angle Layout Technique breaks a layout down into three measurements:

The Drilling Angle
The Pin to Positive Axis Point (Pin-to-PAP) distance
The Vertical Axis Line (VAL) angle

Each measurement has an affect on ball motion. In addition, the relationship between these three measurements affects ball reaction, so all three components and their relationship to one another are important to the final result. Let's lay out a ball, using the Dual Angle Layout Technique, and discuss each component separately. Afterwards, we will discuss their interrelationship, and how they affect ball motion as a whole. The technique begins from a baseline which establishes the starting point for laying out a ball.

If you were to roll an asymmetrical ball along a flat surface, it would eventually roll with the core of the ball either end-over-end (over the position pin) or along a lateral path (with the position pin at the axis point). Typically, a bowling ball layout favors the end-over-end path, and it rolls around it's Positive Axis Point (PSA, or sometimes called the Mass Bias (MB) point.

The Ball's Preferred Roll is over the Position Pin, and around an axis referred to as it's Positive Spin Axis (PSA), sometimes referred to as the Mass Bias point (MB). When creating a ball layout, these two points (the Pin and PSA) are used as our reference points since this is the preferred roll of the ball as it rolls toward the pins.

Reference Points

The ball layout is in reference to two points on a bowling ball.

Asymmetrical Ball

The ball is laid out in reference to a line drawn from the Position Pin and the PSA since the ball core characteristics are unbalanced.

Symmetrical Ball

The ball is laid out in reference to a line drawn from the Position Pin and the Center of Gravity (CG) in a symmetrical ball since the ball is balanced and has no preferred spin axis. After a ball is drilled, all balls become asymmetrical

The line drawn from the Pin and extending through the PSA or CG forms the layout Base Line.

A line drawn from the Position Pin allows us to more precisely place the position where the gripping holes are placed in relationship to the Position Pin. The angle formed between the Base Line and the drawn line is referred to as the Drilling Angle.

The Drilling Angle, affects the length of the skid phase of the ball. The higher the drilling angle, the longer the skid phase of the ball.　 The smaller the drilling angle, the quicker the transition into the hook phase of the ball. The drilling angle limits are 10°-90°

The PAP represents the Positive Axis Point, or the initial axis of ball rotation as it is released. The PAP is the reference point for ball layouts. The Pin to PAP distance (Pin Length) dictates how much flare potential the ball will have as it travels down the lane. The more the ball flares, the more fresh parts of the surface contacts the lane, and the more the ball ultimately hooks.

Flare Potential, is determined by the Total Differential of an undrilled ball. Ball manufacturers measure and publish the ball's total differential (Diff). The higher the total differential, the higher the flare potential. The lower the total differential, the lower the flare potential. The maximum allowed total differential is 0.060" as set by the USBC. The Pin to PAP distance determines how much of that flare potential is used.

The Pin to PAP distance can range from 0" to 6.75". The maximum flare is achieved with a Pin to PAP distance of 3 3/8″. Think of the circumference of the ball as approximately 27". Half way around the ball is 27"/2 or 13.5" (180°). One quarter around the ball, or 90°, is equal to 13.5" / 2 = 6.75". 1/8th the circumference, or 45°, is 6.75" / 2 = 3.375 or 3 3/8". This is the most unstable position of the ball, or the area having the maximum flare potential.

A measured distance from the Pin defines the Positive Axis Point (PAP) location.

The Pin to PAP distance affects the percentage of the flare potential available; the length and total hook. The Locator Pin to PAP distance limits are 0"-6.75".

Stable location - The Pin is located on the PAP (0" Pin-to-PAP).

As you increase towards 2 3/4", flare increases, so the ball typically hooks more overall. Shorter distances results in more boards covered in the hook such as heavier volumes of oil.

Between 2 3/4" and 3 3/8", the ball retains axis rotation longer and thus comes off the break point harder. The maximum track flare is equal to maximum traction. Higher flare decreases total length and increases the total hook of the ball.

Between 3 3/8" and 5", the ball comes off the break point slower, but still strong. Medium distances should be used for medium volumes of oil, but still hook. Lower flare increases total length and lessens the total hook of the ball.

At greater than 5", the ball loses axis rotation quickly and thus is very flat off the spot. Largest distances should be used to play straightest, because the ball will not recover on inside to outside angles.

The Angle to the Vertical Axis Line (VAL)

The Vertical Axis Line (VAL) is a line that passes through the bowler's Positive Axis Point (PAP) and Negative Axis Point (NAP) when extended completely around the ball. The VAL separates the top and bottom of the ball on the bowler's initial axis of rotation. It is parallel to the bowler's grip centerline, and perpendicular to the midline. The VAL is used to establish the placement of the gripping holes.

The Vertical Axis Line (VAL) is established by drawing a line through the PAP at a predetermined angle (the VAL Angle). The VAL angle should be no less than 20° nor more than 70°, and determines how quickly the ball will transition from hook to roll; how long the ball remains in the hook phase.

Minimum 20° angle causes the ball to rev up quickly, and transitions fastest from the breakpoint into the roll.

Maximum 70° angle results in the ball to rev up slowest, and transition slowest from the breakpoint into the roll.

Smaller Angles to the VAL lowers the Radius of Gyration (RG), and increases the total differential of the ball. This results in the ball revving up faster and transitioning faster from the hook into the roll phase of the ball.

Larger Angles to the VAL raises the RG, and decreases the total differential of the ball. This results in the ball revving up slower and transitioning slower from the hook into the roll phase of the ball.

The Drilling Angle affects the length of the skid phase of the ball. The higher the drilling angle, the longer the skid phase of the ball. The lower the drilling angle, the quicker the transition into the hook phase of the ball. The drilling angle limits are 10°-90°.
The Angle to the VAL affects how quickly the ball transitions through the hook phase of the ball; how long the ball remains in the hook phase. The Angle to VAL limits are 20°-70°. Smaller angles rev up faster and transition faster from hook into the roll phase of the ball.
The Locator Pin to PAP distance affects the percentage of the ball's flare potential available; the length and total hook. Lower flare increases total length and lessens the total hook of the ball. The Locator Pin to PAP distance limits are 0"-6.75".

Locating the Gripping Holes

The Midpoint of the Gripping holes are located in relationship to the VAL and PAP. All accurate drilling techniques measure from the PAP back to the Midpoint of the grip using the vertical and horizontal components of the bowler's axis coordinates determined during the bowler's fitting.

The Grip Center Line is parallel with the VAL. It is placed by drawing a Mid-Line which is perpendicular to the VAL.

A point is placed along the VAL using the bowler's vertical axis component and measured from the PAP.

The Mid-Line is drawn from that point and perpendicular from the VAL. Using the bowler's horizontal axis coordinates, the Mid-Line extends from the VAL to the bowlers Center Line. This point is the mid point between the thumb hole to the bottom edge of the finger holes.

The gripping holes are located along the Center Line as determined during the bowler's fitting.

How quickly the ball transitions from skid to hook to roll can be shaped using the sum of the drilling angle and angle to the VAL. The sum of the angles determines how quickly the ball transitions from skid to hook to roll. The smaller sum of the angles changes more quickly.

The shape of the breakpoint is established by the ratio of the drilling angle to the angle to the VAL. The larger the ratio, the later the transition, and the sharper the breakpoint … more back end.

The smaller the ratio, the sooner the ball transitions into a roll.

If the sum of the two angles is small, the ball will transition quickly. If the sum of the two angles is large, the ball will transition slowly. The sum of the angles should be restricted between 30° and 160° to be effective.

The drilling angle should be 10° - 90°, and the angle to the VAL should be 20° - 70°

Small Angle Sums (30-80) should be used for: Long oil patterns (>42') Higher volumes of oil on the lane Speed dominant bowlers High axis tilt bowlers	High Angle Sums (110-160) should be used for: Shorter oil patterns (< 35') Lower volumes of oil on the lane Rev dominant bowlers Low axis tilt bowlers
Medium Angle Sums (80-110) should be used when revs and speed match, and medium oil patterns (36'-40')

Measurement is the first step that leads to control and eventually to improvement.
If you can't measure something, you can't understand it.
If you can't understand it, you can't control it.
If you can't control it, you can't improve it."

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