PBPSI Professional Bowling Pro Shops International Volume #1 - Issue #5 December 2002

Transcription

1 Editor s Corner: Editor: John R. O Dell, PBPSI Membership PBPSI Technical Certification IBPSIA Membership IBPSIA Technical Certification USA Bowling Silver Certification In the December Issue: Locating the Flare Bow Ties Before Drilling the Ball Coming soon to an address near you!!! January: Reverse Layout Taylor Diagrams More Full Roller Taylor Diagrams Some Wierd Layouts and, Still More Numbers February: The Layout of the Ball Vent Holes Pitches and Spans Hurts and Reasons and Fixes Grips and Inserts and Thumb Stuff This newsletter is a continuing education effort of PBPSI. Professional Bowling Pro Shops International PBPSI Professional Bowling Pro Shops International Volume #1 - Issue #5 December 2002 This newsletter is free. It will always be free. You may also elect to have this newsletter sent to individuals that you coach. And, an additional newsletter is also available named The Coaching Eye. Send us a request and we will put each of your students, and yourself if you like, on the list to receive The Coaching Eye (also, always free). It s been a busy holiday season. This is usually one of the busiest time of the year for a pro shop. I hope you all did a fantastic business this season and that you and your family are doing well. So many times we forget what kind of business we are in. Our business is service. That means service to the customer. Any and all knowledge that we can supply the customer is valuable to that customer and invaluable for your continued relationship with that customer. Legal Stuff: Any and all images and text within may be used without permission for educational purposes only in your pro shop and your coaching activities. The only restriction is that you not publish them on any web site or republish any part of the newsletter in any form. Name: PBPSI - Pro Shop Notes Newsletter Membership Information Update your information as you desire. Thank you very much. (Send to usabowlingcoach@hotmail.com) Address:: City: Zipcode: Telephone Number: Fax Number: Address: 2002 PBPSI

2 Professional Bowling Pro Shops International PBPSI The Bow Tie Points also Known as The Flare Axis Points (FAP) How to Estimate Where the Ball will Flare and Whether or not the Flare s will Cross the Finger and Thumb Holes by John R. O Dell PBPSI Membership PBPSI Technical Certification IBPSIA Membership IBPSIA Technical Certification USA Bowling Silver Certification YABA Master Instructor usabowlingcoach@hotmail.com 2002 PBPSI All rights reserved

3 Professional Bowling Pro Shops International PBPSI PBPSI Pro Shop Notes Volume #1 - Issue #5 December 2002 Table of Contents Topic... Page Background Information What Makes a Bowling Ball Flare... 4 What Determines the Total Flare Distance on the Surface of the Ball... 6 Where will the Flare Bow Tie Points (Flare Axis Points) be Located?... 7 Why is it Important to Know Where the Ball will Flare?... 8 Does the Release and layout of the Ball Affect the Flare Characteriistics... 9 Is the Flare Affected by the Lane Conditions? How do the RG and DRG Specifications Affect the Flare Distance and Flare Rate? Simplified vs. Detailed Flaring Model The Model for Flaring Utilized in this Book Wobbling/Flaring on the Lanes Oiled 60 Feet Long and Seemingly 60 Feet Deep Why Worry about the Position of the Bow Ties (FAPs)? Coosing Candidate layouts Based on Probable Bow Tie (FAP) Locations Customer Layout Descriptions Symmetrical Weight Block Layout #1 - RH - Stacked Leverage Layout #2 - RH - Increased Length Layout #3 - RH - Smooth Arc layout #4 - RH - Max Arc - Min Flare Layout #5 - RH - Full Roller Location of the Bow Tie Points (FAPs) Locating the FAP for a Known Ball Assuring a Safe Drilling Layout The Added Step in the Layout Process Reverse Layout of a Bowling Ball (What s coming next month) PBPSI

4 What Makes a Bowling Ball Flare? 4 Shown in the graphic below is a bowling ball that has been released with an axis rotation of 45 degrees with respect to the initial release direction. The ball layout is such that the Pin, CG and the Mass Bias Point are all located on the Initial Leverage Line. All are approximately 3 3/8 inches from the axis of rotation. Most of the reason for flaring comes from the initial Pin position instability. For that reason the graphic on the next page shows the bowling ball modeled with all of the imbalance concentrated at the Pin. Initial Ball Path Direction Primary Flare Axis Point Initial Positive Axis of Rotation Initial Rolling

5 The Single Mass Imbalance Model and the PIN of the Ball Shown in the graphic the right is a cutaway view of a bowling ball that has the weight block PIN orientated away from the initial rolling track. The centrifugal force acts in the direction opposite to gravity; so it acts upward. That force can be divided into two components, one that acts radially outward and one that acts tangential to the surface of the ball. Mass Imbalance Centrifugal Force Mass Imbalance Centrifugal Force Radial Component Single Mass Imbalance Model Centrifugal Force Tangential Component Rolling 5 Ball Center The force that acts radially outward is one of the forces that promotes separation. (Beware high rev bowlers). The other force component is the one that acts along the surface of the ball, the tangential component. It wants to move the pin toward the rolling track. It is that tangential component that causes the flaring to occur. The maximum value for the tangential component of the centrifugal force occurs at an angle of 45 degrees with respect to a horizontal line drawn from the center of the ball to the positive axis of rotation. That 45 degree angle corresponds to what is commonly called the Leverage Line. The leverage line is 3 3/8 from the axis of rotation of the initial rolling track. For a full roller the track is the full circumference of the ball and the positive axis of rotation is 6 3/4 from the initial rolling track. PIN and Mass Imbalance Axis of Rotation 3 3/8" Wobble Single Mass Imbalance Model Maximum Imbalance PIN Location 3 3/8" Rolling Ball Center Axis of Rotation Wobble

6 What Determines the Total Flare Distance on the Surface of the Ball? The Differential Radius of Gyration (DRG) is the ball specification that ultimately determines the amount of flare. Mass Bias Model Single Mass Small Imbalance Model 3D View ZZ RG Axis 6 A ball with zero DRG has no Pin imbalance for the centrifugal forces to act upon. So although the Pin may be located at the Leverage Line at 3 3/8 inches from the axis of rotation, the magnitude of the total centrifugal force is small and correspondingly, the flaring is small. XX RG Axis YY RG Axis If the shape and mass distribution of the weight block is such that the effective mass at the top of the weight block is larger, the DRG is larger and the corresponding instability is larger and the flaring is larger. Mass Bias Model Single Mass Large Imbalance Model 3D View ZZ RG Axis YY RG Axis XX RG Axis

7 Where will the Flare Bow Tie Points (Flare Axis Points (FAP) be Located? The bow ties are the locations (two locations on opposite sides of the ball) where the ball flares about. If you connect those two points with a straight line inside the ball, it forms the axis of the flaring of the ball. The ball flares about the two end points of that line. Hence, the two end points may also be called the Flare Axis Points (FAP). Shown below is a graphic that details why a ball FAP is located above the intersection of a line drawn from the initial axis of rotation (PAP), through the Pin and intersecting the initial rolling track of the ball. If the DRG is small, the difference in the rotational forces is small and the location of the FAP is located on the extended PAP-Pin line at the intersection of the PAP-Pin line and the initial rolling track. If however, the DRG is large, the difference in the sizes of the imbalances at the top and bottom is large (large DRG). For the torques to balance, the location about which the top and bottom imbalance masses rotate about has to move away from the extended PAP-Pin line as shown in the graphic. 7 Non Zero DRG PFAP not at Intersection F1*D1 = F2*D2 PAP Weight Block Top (PIN) Imbalance Mass F1 D1 D2 PFAP F2 Weight Block Bottom Imbalance Mass Note that the point where the ball flares about is not on the line drawn from the PAP through the Pin. It is offset due to the Differential Radius of Gyration, the distribution of the mass in the weight block and ball coverstock combination. Check this out on your own bowling ball. Draw a line from the PAP through the Pin to intersect the initial rolling track. Let s suppose that the Pin is slightly to the right of the index finger for a right handed bowler. The actual FAP is above where the line drawn intersects the initial rolling track.

8 Why is it Important to Know Where the Ball will Flare? If you drill the ball without knowing approximately where the ball will flare, it is possible that the ball will flare over the fingers and or the thumb. Rolling over either the fingers or the thumb hole is a problem and should be avoided if at all possible. And as I recall, PBA may even have a rule that prohibits that situation. Mostly though, if you want to place the Pin at some non-standard location, you had better be careful about how the ball will flare. So, the location of the flare tracks and the Flare Axis Points (FAP) need to be determined ahead of time. As shown on the previous page, the approximate location of the Primary FAP is on the initial rolling track above the intersection point of the extended PAP-Pin line and the initial rolling track. How far above the intersection point depends upon the magnitude of the DRG. But since the DRG values really don t vary that much, the distance offset from the extended PAP- Pin initial rolling track intersection point is about constant. So, that distance can physically be measured. Let s say for example it is measured to be 1 inch offset. That means that the approximate location of the Primary FAP can be located during the layout of the ball and before drilling the ball. Layout the ball as it is to be drilled. Draw an approximate initial rolling track that passes by the fingers and thumb as prescribed by their drill specifications. Draw a line from their PAP through the Pin and extend it to intersect with the initial rolling track. Measure the offset distance from that intersection point. That s the approximate location of the Primary FAP. Locating the other FAP, the Secondary FAP is a little more difficult. The rolling tracks are not full circumference circles on the surface of the bowling ball, so you can t just rotate the ball 180 degrees and locate the point. you must draw a better approximation of the initial rolling track based on the secondary PAP, the point on the side of the ball opposite to that of the PAP. It is exactly 180 degrees away from the PAP. So, locate the Secondary PAP and draw a circle on the surface of the ball passing through the approximate initial estimate of the initial rolling track passing near the finger and thumb holes and also intersecting the Primary FAP. The Secondary FAP will be 180 degrees from the Primary FAP on that initial rolling track. So now you have both FAP s located without ever drilling the ball. The final concern is where a weight hole will be located after the ball is drilled. If you have a non-standard drill layout and you do not check where the ball will flare and where a weight hole will be located, the ball might also roll over the weight hole. That s equally a bad idea and equally bad as far as PBA is concerned. 8 For some non-standard layouts, the location of the PFAP, the SFAP and the flare tracks must all be located prior to drilling. Creativity has it s costs doesn t it.

9 Does the Release and Layout of the Ball Affect the Flare Characteristics? 9 The answer is no, but with some qualification. It s mostly the magnitude that changes, not the absence of flare totally. Hand Position at Release Straight Behind the Ball: When a bowler releases the ball with their hand absolutely in back of the ball in line with the direction of the release of the ball, there is no sideways rotation imparted to the ball. The ball has no reason to break inward from the initial direction of the release of the ball. It will go pretty straight down the lane, regardless of the drilling layout of the ball. There s no reason for the ball to break inward. But, does the ball flare. Yes. The amount that it flares depends upon the drilling layout and the Differential Radius of Gyration. The larger the Differential Radius of Gyration and the more unstable the Pin layout position, the greater the ball will flare. So, the ball will have flare tracks showing that the ball is trying to get the Pin to that rolling on the track position. Some Sideways Rotation: Normally the ball is released with the hand just a little to the side of the direction of the release of the ball. That creates a rolling track that is just to the side of the drilling layout. It s commonly called a 3/4 roller release. Does the 3/4 roll release exhibit flaring? Yes, and the ball will tend to break inward if given the opportunity by the presence of friction at the backend of the lane surface because the to the side release causes sideways rotation on the ball. The ball will release that sideways energy by interacting with the friction of the ball and lane surface. The lane friction actually does work on the ball. The lane friction interacts with the ball surface friction and pulls energy out of the ball. Since some of that energy is sideways rotation, the ball is pulled sideways in the direction that the ball is rotating sideways. So, the lane does some work on the ball, moves it sideways and decreases the amount of sideways energy in the ball by the amount that corresponds to the distance moved laterally across the lane. So does the ball flare? Yes. Remember while all of that other stuff is happening, the Pin may be positioned at a unstable position with respect to the initial axis of rotation and the rolling track. So, the ball will flare dependent upon the Pin position and the DRG specification of the ball. The Rev Rate: The initial rotation rate that a bowler imparts to the ball, the Rev Rate, is the one bowler release parameter that has the greatest influence on the actual flare distance achieved on the surface of a specific bowling ball. The higher the Rev Rate, the greater the probability that the flare distance on a specific bowling ball will be greater.

10 Is Flare Affected by the Lane Conditions? 10 The answer is yes. Very wet lane conditions will drain the energy of the ball only slightly, whereas very dry conditions will drain the energy of the ball very rapidly. Since the energy of the ball on very dry lane conditions is being decreased rapidly as it rolls down the lane, the corresponding centrifugal forces causing flaring is also decreasing. So, for very dry lane conditions, the flaring rate (the speed at which the ball spins about the bow tie points (the Flare Axis Points), decreases. Flaring gets slower as the ball rolls down the lane. For very wet lanes, the decrease is minimal but it is there nonetheless. And when you roll the ball on wet and then dry conditions, the ball flares more or less constant during the time in the oil, but starts slowing down as it rolls further in the dry lane condition. How Do the RG and DRG Specifications Affect the Flare Distance and Flare Rate? They are two different critters. RG affects the distance between the flare tracks. Since a low RG ball is easier to rev up, it is easier to make the ball rotate. For two balls drilled exactly alike and the DRG vales are exactly alike but the RG values are very different, the one with the lower RG value will have oil tracks closer together. It s easier to rotate the lower RG ball. Large DRG corresponds to a large total flare distance on the ball. The large DRG means the ball has a greater need to keep flaring. The centrifugal forces causing flaring act on the mass distributions of the ball most exhibited by the DRG. If the DRG is large, the need to flare caused by the weight block design is large. But..... (there s another one of those big butts). The drilling layout of the ball creates the unstable environment for the flaring to occur. If the ball has a high DRG specification and the ball layout places the dynamics of the ball (Pin, CG and MBP) in an unstable initial state, the ball will tend to exhibit the flare characteristics designed into the weight block design. If, however, the layout places the dynamics of the ball in a very stable state (like the Pin on the PAP and the MBP on the track), the ball will not exhibit much flaring at all. The layout has essentially nullified the flare designed into the weight block. So, the correct statement to make about the effect of DRG on flare is that based on DRG alone, the ball has a certain flare potential. The higher the DRG, the greater the flare potential. The actual flare realized is dependent upon the instability of the layout of the ball. The greater the layout instability, the greater the actual flare distance realized.

11 Simplified vs Detailed Flaring Model 11 The Taylor Diagrams utilize the Simplified Flaring Model as shown to the right. The Detailed Flaring Model shown below is a more accurate model if you already know exactly where the FAP is located and what the release characteristics are for that bowler (a 3/4 roller, a spinner, a full roller???). FRT Pin PAP IAR The reason the Simplified Flaring Model is used for the Taylor Diagrams is because there are an infinite number of combinations of FAP locations and release styles. MRT IRT MBP CG The Taylor Diagrams are a good tool for showing general characteristics of a ball layout without prior knowledge of the bowler s exact release characteristics. The Taylor Diagrams can be utilized to pick a general characteristic of the dynamic needs of the weight block. FRT FAP The Pro Shop Technician that does the layout can use the Taylor Diagram initially and then slightly modify the arrangement to best fit that specific bowler s release style. MRT Pin CG PAP IAR Use the Taylor Diagram. It s a excellent starting point. But remember it s just a tool to help you get to that final goal of a proper layout and a good fit for your customer. IRT MBP

12 The Model for Flaring Utilized in this Book For a full roller the track is the full circumference of the ball and the positive axis of rotation is 6 3/4 from the initial rolling track. Shown in the figure below is a graphic of a 3/4 Roller where the rolling track is shifted to the side of the fingers and thumb. Although the rolling track is not the full circumference of the ball for a 3/4 roller, it is drawn that way merely for convenience. It is just a model, nothing more. The graphic shows a ball that has been released with the rolling track at 45 degrees away from the initial release direction. That s also called 45 degrees of axis rotation. 12 Ball Path Direction Primary Flare Axis Point 45 degrees Initial Positive Axis of Rotation Initial PIN Wobble (the Path of the PIN) Initial Rolling An example of flaring appears on the following pages.

13 Wobbling/Flaring on Lanes Oiled 60 Feet Long and Seemingly, 60 Feet Deep The series of graphics shown below detail a very smooth surface bowling ball released with equal sideways roll and forward roll on very very wet lanes. (The ball never wrinkles; it slides the whole 60 feet; it never breaks across the lane, but it does wobble and consequently flare throughout the entire rolling path, which in this case is a straight line). 13 Ball Path Direction Super Wet Initial just after Release Primary Flare Axis Point Initial Positive Axis of Rotation Initial PIN Wobble Initial Rolling

14 14 Ball Path Direction Primary Flare Axis Point Super Wet #2 Current Positive Axis of Rotation Ball Path Direction Current PIN Wobble Current Rolling Primary Flare Axis Point Super Wet #3 Current Positive Axis of Rotation Current PIN Wobble Current Rolling

15 Ball Path Direction 15 Primary Flare Axis Point Super Wet #4 Current Positive Axis of Rotation Ball Path Direction Current PIN Wobble Current Rolling Primary Flare Axis Point Super Wet #5 Current Positive Axis of Rotation Current PIN Wobble Current Rolling

16 Ball Path Direction 16 Primary Flare Axis Point Super Wet #6 Current Positive Axis of Rotation Current PIN Wobble Current Rolling Ball Path Direction Primary Flare Axis Point Final Super Wet Note that the flaring distance for this model is 6 3/4 which is 1/4 the circumference of the ball. Final PIN Wobble & Final Rolling Final Positive Axis of Rotation

17 Why Worry about the Position of the Bow Ties (FAPs)? 17 Thump, thump, thump, thump And, from the control desk comes the announcement... Ladies an gentlemen we d like to have your attention. Bowling on lanes 13 tonight, John O Dell just left the Nice ball John. Two things can happen when your bowling ball rolls over either the thumb or finger holes. Both of them are bad. The ball has less traction since a percentage of the time it is trying to roll over an area on the ball where there is no friction surface. And the ball will tend to hop into the air each time it gets to the hole. Airborne bowling balls have no traction at all and they correspondingly don t hit very well. Is Your Bowling Ball Rolling over any of the Gripping Holes? The initial rolling track is easy to see whether it is rolling over the thumb hole and, in fact you can probably hear that noise since it occurs so close to your release of the ball. Check where your rolling track is located with respect to the thumb hole. That first track should be away from both the finger and thumb holes by at least 1/4 inch. The detection of whether the ball is rolling over the finger holes is a little more difficult. Those final rolling tracks are difficult to actually see on the surface of the ball after it comes back to the ball return. You can predict the occurrence of thumping by simply finding the FAP and projecting the rotation of the flare lines. Locate the FAP and estimate how far around the ball the actual flare will be. A better way is to go out to the bowling center very early in the morning before any leagues start. Roll the ball normally. Since there is no one else bowling, you should be able to hear the thumping if it occurs. It s a terrible sound..... please don t ask me how I know.

18 Choosing Candidate Layouts Based on Probable Bow Tie (FAP) Locations Remember the general rules for layout of a bowling ball. 18 As the Pin gets closer to the PAP, it will tend to arc. As the Pin gets farther away from the leverage line and from the PAP, the ball will tend to go longer and snap. As the Pin gets lower and closer to the midline, the ball will tend to roll early. As the Pin gets higher above the midline, the ball will tend to go longer. What s not explicitly stated in the rules is the location of the FAP and the possibility of thumping. You as a ball driller must always consider the location of the FAP and whether or not the ball will flare over either the thumb or the finger holes. The following pages will go into great detail on finding the FAP for a specific layout. First, some standard layouts without consideration of the FAP locations will be listed.

19 Symmetrical Weight Block - Layout #1: Stacked Leverage - Right Handed Bowlers - 19 Pin 3 3/8" PAP Midline CG 3 3/8" PAP Vertical Axis Distance Grip Center PAP Midline Distance Graphic Provided by Professional Bowling Pro Shops International 2003 Drilling Instruction Manual 2003 PBPSI All Rights Reserved Grip Centerline MBP The location of the Mass Bias Point will depend upon the design of the weight block. It is included here for convenience as a MBP that is apporximately 6 3/4 from the Pin. Layout Impact on the Roll of the Ball: This drilling provides maximum flare for the ball. Purely from the dynamic desires of the weight block, the higher the Pin is located from the midline, the longer the ball will skid before it starts to hook. That length to hooking is always effected by the surface of the ball. Generally, the rougher the surface, the earlier the ball will ball will start to hook. But regardless of the surface, this layout will promote maximum flaring and the most surface will be exposed to the lane surface. High rev bowlers beware. Your high revs may cause the ball to flare all the way around the ball surface. (Thumpity, thumpity, thumpity, thump, thump, thump). For medium and low rev bowlers this is a great layout. Note to the Bowler: Recommendations from the Pro Shop -

20 Symmetrical Weight Block - Layout #2: Increased Length - Right Handed Bowlers - 20 Desired CG Offset Midline Pin 4 1/2 to 5 1/2" CG PAP PAP Vertical Axis Distance Grip Center PAP Midline Distance Graphic Provided by Professional Bowling Pro Shops International 2003 Drilling Instruction Manual 2003 PBPSI All Rights Reserved Grip Centerline MBP The location of the Mass Bias Point will depend upon the design of the weight block. It is included here for convenience as a MBP that is apporximately 6 3/4 from the Pin. Layout Impact on the Roll of the Ball: This drilling provides increased length for the ball. Purely from the dynamic desires of the weight block, the farther the Pin is located away from the Initial Axis of Rotation (PAP), the longer the ball will skid before it starts to hook. That length to hooking is always effected by the surface of the ball. Generally, the rougher the surface, the earlier the ball will ball will start to hook. So for really increased length, make sure the surface is smooth. The smoother the surface, the longer the length. The snapiness at the backend will depend upon the aggressiveness of the coverstock on a dry lane surface. This layout is also good for drier conditions (it allows the ball to get farther down the lane before the weight block dynamics kick in). Note to the Bowler: Recommendations from the Pro Shop -

21 Symmetrical Weight Block - Layout #3: Smooth Arc - Right Handed Bowlers to 1 1/2" Desired CG Offset Midline CG Pin PAP PAP Vertical Axis Distance Grip Center PAP Midline Distance Graphic Provided by Professional Bowling Pro Shops International 2003 Drilling Instruction Manual 2003 PBPSI All Rights Reserved MBP Grip Centerline The location of the Mass Bias Point will depend upon the design of the weight block. It is included here for convenience as a MBP that is apporximately 6 3/4 from the Pin. Layout Impact on the Roll of the Ball: This drilling provides promotes a smooth arc rolling path for the ball. Purely from the dynamic desires of the weight block, the closer the Pin is located to the Initial Axis of Rotation (PAP), the shorter the ball will skid before it starts to arc toward the pocket. That length to arcing is always effected by the surface of the ball. Generally, the rougher the surface, the earlier the ball will ball will start to arc. So for really increased length, make sure the surface is smooth. The smoother the surface, the longer the length. The snapiness at the backend will depend upon the aggressiveness of the coverstock on a dry lane surface. This layout is also excellent for drier conditions (it allows the ball to get farther down the lane before the weight block dynamics kick in which, in this case, are small). Note to the Bowler: Recommendations from the Pro Shop -

22 Symmetrical Weight Block - Layout #4: Maximum Arc - Minimum Flare - Right Handed Bowlers - 22 Desired CG Offset Midline CG Pin at PAP PAP Vertical Axis Distance Grip Center PAP Midline Distance MBP Graphic Provided by Professional Bowling Pro Shops International 2003 Drilling Instruction Manual 2003 PBPSI All Rights Reserved Grip Centerline The location of the Mass Bias Point will depend upon the design of the weight block. It is included here for convenience as a MBP that is apporximately 6 3/4 from the Pin. Layout Impact on the Roll of the Ball: This drilling provides promotes the maximum smooth arc rolling path for the ball. Purely from the dynamic desires of the weight block, when the Pin is located on the Initial Axis of Rotation (PAP), the ball will tend not to flare at all. The Pin is at one of it s stable locations on the surface of the ball. Generally, the rougher the surface, the greater the ball will arc. So for really increased length, make sure the surface is smooth. The smoother the surface, the longer the length. The snapiness at the backend will depend upon the aggressiveness of the coverstock on a dry lane surface. This layout is the best possible layout for super dry conditions (it allows the ball to get farther down the lane before the weight block dynamics kick in which are essentially zero). Note to the Bowler: Recommendations from the Pro Shop -

23 Symmetrical Weight Block - Layout #5: Full Roller - Right Handed Bowlers - 23 Grip Centerline Grip Center Initial Rolling MBP PAP Midline Distance CG PAP Vertical Axis Distance PAP Midline Graphic Provided by Professional Bowling Pro Shops International 2003 Drilling Instruction Manual 2003 PBPSI All Rights Reserved Pin 1" Max The location of the Mass Bias Point will depend upon the design of the weight block. It is included here for convenience as a MBP that is apporximately 6 3/4 from the Pin. Layout Impact on the Roll of the Ball: This drilling provides a safe layout for a full roller release. Purely from the dynamic desires of the weight block, the layout will tend to provide good length for the rolling path. Generally, the rougher the surface, the earlier the ball will start to hook toward the pocket. So for really increased length, make sure the surface is smooth. The smoother the surface, the longer the length. The snapiness at the backend will depend upon the aggressiveness of the coverstock on a dry lane surface. If the bowler has a full roller release and a high rev rate, the Pin should actually be closer to the initial rolling track than shown in the diagram. (Usually full rollers don t have high rev rates). Note to the Bowler: Recommendations from the Pro Shop -

24 Locating the FAP for a Known Ball Example:Stacked Leverage - 3/4 Roller - Right Handed The location of the Bow Tie (FAP) is shown by the graphic below. As you can see, the location is not on the line drawn from the PAP through the Pin. It is offset above the intersection of that line and the initial rolling track. Recall back on page 7 that the reason for the offset was explained. That offset distance is another approximate standard parameter that can be used for the bowler except that it is more related to the DRG than the bowler s release. The higher the DRG, the greater the offset distance. So, if you know the DRG of the ball on which the FAP Offset Distance was measured, that distance will be greater if the candidate ball has a higher DRG and smaller if the candidate ball has a lower DRG. (The actual differences may be quite small) Note that this is only a qualitative approximation. You cannot estimate the exact location. You can only determine that it is smaller or larger. Heh, that s better than no knowledge at all! Extended PAP-Pin Line 24 FAP Offset Distance (FOD) FAP 90 Pin Estimated 6 3/4" Flare Line Midline 3 3/8" PAP Grip Center CG 3 3/8" PAP Vertical Axis Distance (VAD) Initial Rolling MBP Grip Centerline PAP Midline Distance (MD)

25 25 This graphic is a little less busy than the previous graphic. It shows where the approximate flare limits are and the clear indication that the flare lines will not be a problem with respect to rolling over the Finger or thumb holes. FOD FAP 90 Estimated 6 3/4" Flare Line Pin 3 3/8" PAP CG 3 3/8" VAD MD MBP But... if the bow tie point is truly at the end of the axis of the flaring (the Flare Axis Point FAP), there is also another FAP on the other side of the ball opposite to the FAP shown on the above graphic. And... we must equally be concerned with the location of the flaring about that FAP also. So for convenience that other flaring axis point will be called the Secondary Flare Axis Point (SFAP). The graphic on the following page shows the SFAP on the opposite side of the ball.

26 26 Note that the SFAP is on the opposite side of the ball. The location can be approximated as 180 degrees from the FAP. So any two circles drawn through the existing known FAP at 90 degrees from each other will intersect at the SFAP as shown in the graphic. Note also that generally the FAP is above and to the left of the finger holes for this layout (stacked leverage) and the SFAP is below and to the right of the thumb hole. So there are inherently safe zones for this layout based upon the location of the FAP and SFAP. The next graphic shows the safe zones. Flare Axis FAP SFAP On the opposite side of the ball from the FAP. Flare Axis Another Note: The FAP that is located by drawing a line from the PAP through the Pin, extending that line to intersect the initial rolling track and then offsetting that intersection point by the approximated offset distance is defined as the FAP. The other end of the axis of flaring is defined as the SFAP. This will come into play later when we layout the ball on the side of the ball opposite to the label of the ball. It s called reverse drilling and maximizes the measured top/bottom static weight as well as the hitting power of the ball. Later gator.

27 27 Note the safe flaring zones based upon the location of the FAP and the SFAP. It is the responsibility of the Pro Shop Operator to correctly layout the ball so that the thumb and finger holes do not intersect with the safe flaring zones. If any of the holes intersect with the safe flaring zones, it s no longer safe flaring is it? General considerations: The top side flaring lines rotate from the initial rolling track around the ball to about 90 degrees from the initial location for a 6 3/4 flare potential bowling ball when an average rev rate release is imparted upon the ball. That locates the flare lines to the left and above the finger holes. Note that there is a zone between the flare zones on the top of the ball. It s okay to locate a weight hole in that area (gee, I surely hope that you don t need to). The bottom side flaring lines rotate from the initial rolling track around the ball in the same way. That locates the flare lines to the right and below the thumb hole. Remember that the SFAP shown below is on the back side of the ball The next graphic shows the safe flaring zones and the safe drilling zones. An effort should be made to always keep them apart.. Flare Axis On the Top of the Ball FAP Initial Rolling SFAP Flare Axis On the Bottom Backside of the Ball

28 So, about 1/2 of the ball is safe for flaring and 1/2 of the ball is safe for drilling. 28 Heh, it s a piece of cake, right..... Safe Flaring Zone Safe Drilling Zones Safe Flaring Zone Note that these graphics are only approximations. The top left safe drilling zone may be a little smaller or larger and the bottom right may be a little larger or smaller depending on the type of release (how much spin). Initial Rolling The greater the spin, the farther the flaring axis is pushed away from the center of the ball. The graphic shown is for a flaring axis directly through the center of the ball. A 3/4 roller will only be separated a little to the left of the center of the ball. Safe Drilling Zone Safe Flaring Zone PAP Safe Flaring Zone Safe Drilling Zone So for the purposes of modelling and the layout of the ball remember where the approximate safe zones

29 Assuring a Safe Drilling Layout For front side drilling layouts, the primary concern is the FAP location with respect to the finger holes. Let s assume that you have been requested to place the Pin at a non-standard position by the bowler..... It is your responsibility to show the bowler that the ball may flare over the finger holes. Here s an example: The bowler asks you to place the Pin at the center of the grip and the MBP well below the PAP. (You already have his release measurements including his FAP Offset Distance). Did I mention that the ball has a 6 3/4 inch flare potential? Lay the ball out before drilling and show him that the ball will probably flare right over the finger holes. Here s the bad news. 29 Initial Rolling PAP Midline FAP Pin PVD MD FAP Offset Distance CG MBP Grip Center Grip Centerline Thumpity, thumpity, thumpity, thump, thump, thump. No, that s not the sound of the Lone Ranger s horse Silver galloping across the prarie. It s the sound of a bowling ball becoming airborne each time the ball rolls over a finger hole. If however the ball only has a 1 inch flare potential the ball layout might be okay as shown. Good luck.

30 The Added Step in the Layout Process Layout the ball as you desire. The only extra step that needs to be taken is the one that assures that the ball will not flare over the thumb or finger holes. So, as the example on the previous page shows, take that extra step. The following assumes that you have the bowler s release parameters and the FAP Offset Distance. Here are the Steps: 1. Lay out the ball. 2. Draw the PAP-Pin line. 3. Extend the PAP-Pin line to intersect the estimated Initial Rolling. 4. On the initial rolling track from that intersection point, determine the FAP from the FAP Offset Distance from that point of intersection. 5. Estimate the flaring lines around the ball surface by determining the final flaring line location. Examples: 3 3/8 inches Flare Potential = 45 degrees about the FAP. 6 3/4 inches Flare Potential = 90 degrees about the FAP /8" Final Flare Line PAP FAP Midline FAP Offset Distance Pin CG 6 3/4" Final Flare Line MBP Grip Centerline As you can see, knowledge of the flare potential is critical.

31 Reverse Layout of a Bowling Ball What the heck is that? 31 Well, suppose that you wanted to get the highest possible static top/bottom weight in a bowling ball. How would do it? There are several ways. One is to pick a bowling ball to be drilled that already has a large top weight. remember though that you are going to lose several ounces by drilling holes in the ball. The other usual option is to drill a massive weight hole to bring the static top/bottom weight to about the amount desired. But why would you want to maximize the static top/bottom weight? That s an easy one. The greater the top/bottom weight, the greater the final rotational inertia if you can get the Pin to be located on or near the final rolling track just as it impacts the pocket So... how do you maximize the top/bottom weight for greater hitting power and how do you lay out the ball out to get that greater hitting power? Find out next Month in the Volume 2 - Issue #1 January 2003 of the PBPSI Pro Shop Notes. Happy New Year and the very best to you and your family. Have a great 2003 guys. Nobody deserves it more than you.