From: ak331@cleveland.Freenet.Edu (Jerry A. Jelinek)
Newsgroups: alt.sport.bowling
Subject: Re: Questions for the FAQ
Date: 12 Jan 1993 23:52:30 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: thor.ins.cwru.edu


Walter Perz asks:
 
>I have a couple of questions for the FAQ list.  Could there be a summary of  
>how different drilling patterns on a ball will affect its reaction?  This  
>has been discussed recently, and every time I think I follow what is going  
>on, but then I think was it side weight or finger weight that makes the ball  
>go longer through the heads and then snap like a bat from heck?   
 
>And also, how does pin placement affect this? 
 
>Is there a book or literature that I can buy at a pro-shop or a book store? 
 
The best book I have is "Bowling: Knowledge is the Key" by Fred Borden.  This
book is several years old (1985 - First Printing).  It is an excellent 
reference book about bowling in general.  It does not discuss axis vs. 
leverage weighting.  It does discuss thumb, finger, side and top weight.
 
I have a old copy of Bowlers Journal (July 1986) which discusses axis and
leverage drilling.  The author (Bob Strickland) discusses and judges which
drilling is best.  If people would like, send me private email and I can 
arrange to send a copy of the article to you.
 
Here is a summary:
 
Remeber that a undrilled bowling ball has more weight near the surface of the
ball. Why?  Because drilling the holes for your fingers removes weight.  The
weight near the surface (aka weight pin) is there to compensate for the 
drilling process.  Some smart people thought, ok I won't drill the finger 
holes over the pin!! Ahha - I can create a gyroscopic effect and get more 
roll.  That is the whole principal of "unconventional" drilling.
 
Each one of the types of weight drilling is designed for a specific goal.
There is no one ideal weight drilling.  Different balls with different 
drilling will react very differently.  This makes the choice of drilling
techniques a "black magic" art form.  But with a little knowledge, even the
average bowler can understand why Joe Schmuck bowler can average 190, while
you may only averge 160 on the same condition with the same ball.
 
BACKGROUND:
Because all drilling is based on weight pin placement here is my ascii 
representation of a typical ball:
 
             
            ...
           /   \
          /     \
         /       \
        !  H   H  !
        !         !
        !    P    !
        !         !
         \   H   /
          \     /
           \.../
            
 
Legend : H - Finger and thumb hole,  P - Weight Block (aka pin)
 
With no additional holes, the above represents a ball with no thumb, side,
finger etc..
 
FINGER WEIGHT:
When the Pin is placed closer to the finger holes:
 
 
            ...
           /   \
          /     \
         /       \
        !  H   H  !
        !    P    !
        !         !
        !         !
         \   H   /
          \     /
           \.../
            
 
This is called finger weight.  Finger weight is designed to make the ball
role longer.  The ball skids longer and hooks later.
 
THUMB WEIGHT:
When the Pin is placed closer to the thumb hole:
 
 
            ...
           /   \
          /     \
         /       \
        !  H   H  !
        !         !
        !         !
        !    P    !
         \   H   /
          \     /
           \.../
            
 
This is called thumb weight.  Thumb weight is designed to make the ball
role earlier.  The ball will hook earlier and skid less than finger weight.
So for oily conditions, thumb weight is usually preferable, because the ball
gets into its roll earler and begins hooking earlier. 
 
On drier conditions, finger weight is usually preferable because the ball 
will skid longer and won't "roll out" as a thumb weight ball might.
 
POSITIVE WEIGHT: (This is for right handers, left handers should reverse the
                  pin placement)
 
            ...
           /   \
          /     \
         /       \
        !  H   H  !
        !         !
        !        P!
        !         !
         \   H   /
          \     /
           \.../
           
 
This is positive side weight.  Positive side weight will make the ball spin
more than zero side weight.  The ball will spin more, therby hook more.  
Most bowlers use exclusively zero side weight or positive side weight.
 
 
NEGATIVE WEIGHT: (This is for right handers, left handers should reverse the
                  pin placement)
 
            ...
           /   \
          /     \
         /       \
        !  H   H  !
        !         !
        !P        !
        !         !
         \   H   /
          \     /
           \.../
            
 
This is negative side weight.  Negative side weight will flatten the roll
of the ball.  The ball will spin less and therby hook less.
 
The way I like to think of side weights is that positive side weight will
create more side revolutions while negative side weights will create more
of a forward action.  Either weighting can work of oily or dry conditions.
Because most of use are part-time bowlers, either zero or positive weighting
is best for us.  I personally use either zero or positive side weight.  I 
have never tried negative weighting because my drilling pro, never 
recommends negative weight. (I'm a scratch bowler and trust my drilling pro)
It is important to discuss any drilling techniques with your drilling pro.
DON'T EVER GET A BALL DRILLED AT KMART.
 
For top and bottom weight we must change our few of the ball for a top down
view to a side view:
 
           /XXXXX\    
          X H P H X
         X         X
         X         X
         X         X
         X         X
          X       X 
           \XXXXX/
 
This is a side view with our H - holes and P - weight block.
 
TOP WEIGHT:
           /XXXXX\    
          X H P H X
         X         X
         X         X
         X         X
         X         X
          X       X 
           \XXXXX/
 
The weight block is placed on the top half of ball. 
 
BOTTOM WEIGHT:
           /XXXXX\    
          X H   H X
         X         X
         X         X
         X         X
         X         X
          X   P   X 
           \XXXXX/
 
The weight block is placed on the bottom half of the ball.
 
ABC doesn't allow more then 3 ounces difference between the top and bottom
of the ball. Bottom weight would result in a ball that would roll too early
in the heads of the lanes.  With this extreme early roll the ball would be
much less effective in the back end of the lanes, thus creating a "roll out"
effect.  It is because of this that bottom weight is not recommended.
 
Before we begin axis vs. leverage weighting we add a new variable to the
differences between weight drilling; your bowling track.  Because each one
of us rolls the ball differently we each create a different track on our
bowling ball.  Most of you are familar with the terms full roller, semi 
roller or more commonly called 3/4 roll, and spinner.  I won't go into detail
about each type, I'll leave that to the many bowling books available. The
most important thing is to remember that axis and leverage weight is refering
to how the weight block is placed relative to your bowling ball track.
 
Below represents the top view of my bowling ball:
 
           /XXXXX\                           
          X       X                     
         XT H   H  X                             
         X T       X                             
         X T       X                              
         X  T H    X                            
          X  T    X                           
           \XXXXX/                              
 
H - Holes for thump and finger , T - Ball track (Semi or 3/4 roll).
 
We add two more terms to the weight drilling vocabulary, dynamic and 
static balance.
 
PERFECT BALANCE:
"The center of gravity and the center of the densest mass within the bowling
ball rest precisely at the geometric center of the ball." by Bob Strickland
Bowlers Journal July 1986.  This sounds complicated, but this is simply a
formal way of explaining a tradition ball drilling, where the weight block
or the center of the pin is between the thumb and fingers:
 
           /XXXXX\    
          X       X
         X  H   H  X
         X         X
         X    P    X
         X         X
          X   H   X 
           \XXXXX/
 
There is no top, bottom, side, finger or thumb weight.  The ball is perfectly
balanced from any weight point.
 
 
STATIC IMBALANCE:
"The center of gravity of the ball lies somewhere other than at the geometric 
center of the ball." by Bob Strickland.
This describes when the weight block is placed to create finger, thumb, side,
top or bottom weight.  Basically anytime the pin is placed anywhere but 
between the finger and thumb can be thought of statically imbalanced.
 
DYNAMIC IMBALANCE:
This has the same definition as static imbalance, huh?!?!. Thats right, but
this can't be measured when the ball is at rest. O.K.?!?!. It is measured
when the ball is in motion, thus the term dynamic.  So a ball can be 
statically balanced, but dynamic imbalanced.  
 
Remember that a ball can only have 3 ounces top weight.  So a ball can be
balanced on the "dodo" (this is the device used to measure the static balance
of a ball), and still be balanced. But when thrown becomes dynamically 
imbalanced.  This creates a gyro effect, thus increasing hooking power.
 
OK FOLKS - 
Is everybody ready for the difference between axis vs. leverage? Don't answer
that. Here goes.
 
AXIS WEIGHT:
The ball is drilled very much like a tradition drilling:
 
           /XXXXX\                           
          X       X                     
         XT H   H  X                             
         X T       X                             
         X T  P   <                              
         X  T      X                            
          X  TH   X                           
           \XXXXX/                              
           
This represents my ball with axis weight.  The pin is placed between the
fingers and thumb, but a weight hole is drilled on the center of the axis.
Thus the term axis weight.  This ball is still statically and dynamically
balanced, but with a weight hole on the opposite side of the track, the ball
weighs more on the track side and thus hooks more.  This is not side weight,
but a overall ball imbalance on the track side.  
 
This drilling is easy to spot when a bowler has it.  Watch the ball as it
rolls to the pocket, If you see a hole spinning to the pocket, that is axis
drilling.  I'll summarize Bob Stricklands characteristics in a moment.
 
LEVERAGE WEIGHT:
This represents a ball which has a dynamic and maybe a static imbalance.
 
           /XXXXX\                           
          X       X                     
         XT H   H  X                             
         X T       X                             
         X T     P X                             
         X  T      X                            
          X  TH   X                           
           \XXXXX/                              
           
This ball is dynamically unbalanced because as the ball rolls, the weight
block moves not around the gemoetric center of the ball, but around some
other point.  The ball may or may not be statically balanced.  If the a 
weight hole is drilled on the bottom to equal the amount of top weight 
created by the pin placement, then the ball is still statically balanced.
 
This makes the ball react violently on the lanes.  This is the extreme form 
of "unconventional" drilling techniques, because the ball has a extreme 
gyroscope effect.
 
Ok, I know the above is hard to take in at one time.  I highly recommend
talking with your drilling pro and he/she can explain the above much better.
 
Here is Bob Stricklands opinion of balanced, axis and leverage drilling:
 
BALL TYPE       BALANCE         AXIS    LEVERAGE
Degree of hook    **            * *       * *
Degree of skid    **           * * *     * * *
Angle of Attack   **           * * *     * * *
Impact Force      **          * * * *    * * *
Consistency       **            * *        *
 
1 star is minimum, 4 stars is maximum.
 
Mr. Strickland recommends either balanced or axis drilling.  He doesn't
recommend the leverage drilling because it is dynamically imbalanced and
requires a high degree of consistency in your release.  If you are a scratch
bowler, then any of the drillings can work for you.  For lower average 
bowlers use a balanced or axis drilling.
 
Remember always talk to your local drilling pro for the best drilling for
your game.
 

Jerry