This two confuse me all the time and the following are what I understand:

1. When I release my ball at the foul line (assume I'm a stroker and style is 10 10), my hand is completely behind the ball and roll forward.

in this case, the ball axis is parallel to the foul line, therefore the axis rotation 0 degree because axis rotation is measured the angle between the ball axis and the horizontal line.

in terms of axis tilt, it is 90 degree because axis tilt is measured the angle between the ball axis and the vertical line. the ball axis is also 90 degree angle as compared to the gutter - but this one I dont know the term to describe it.

2. When I release my ball at the foul line (again assume I'm a stroker and style is 10 10), my hand is completely at the side of the ball and rotate counter clock-wise (right-hander).

in this case, the ball axis is 90 degree angle to the foul line, therefore the axis rotation 90 degree.

in terms of axis tilt, it is also 90 degree as compared to the vertical line. the ball axis however is 0 degree angle as compared to the gutter.

3. When I release my ball at the foul line (again assume I'm a stroker and style is 10 10), my hand is completely at the side of the ball and move forward (right-hander), commonly known as spinning the ball.

in this case, the ball axis is 90 degree angle to the foul line, therefore the axis rotation 90 degree.

in terms of axis tilt, it is also 0 degree as compared to the vertical line. the ball axis however is 90 degree angle as compared to the gutter.

4. When I release my ball at the foul line (again assuming I'm a stroker and style is 10 10), my hand is half at the back of the ball and half at the side of the ball and rotate counter clock-wise (right-hander) ie 45 degree release.

in this case, the ball axis is 45 degree angle to the foul line, therefore the axis rotation 45 degree.

in terms of axis tilt, it is also 45 degree as compared to the vertical line. the ball axis is also 45 degree angle as compared to the gutter.

Now:

If someone asks tell me to increase my axis rotation, that means I have to place my hand more to the side of the ball.

If someone ask me to increase my axis tilt, that means I have to make the ball axis lessor angle to the gutter and larger angle to the vertical line. To do that I have to place my hand more to the side of and under the ball and rotate counter clock-wise.

Can anyone tell me whether I'm correct and pinpoint where are the wrongs.

To do an accurate discussion of this topic ,we must establish the difference between axis of rotation and axis tilt .Some times people use thes terms interchangebly , they are NOT .They have a different meanings. Axis of rotation is define as how far the axis of rotation is rotating from a pure forward roll in the horizontal direction ,wich is measured in degrees.

Axis tilt is defined as how far the positive end of the axis of rotation is above the middle of the ball measured in degrees .

Axis of rotation is in the horizontal plane while axis tilt is in the vertical plane .I hope this will help you understand a little more.

Ray200 I'm sorry to say your words don't help me a cent.

Hi Maf south,

Let me give it a shot...

Let's view the ball from the top for the explanation of axis of rotation:

........***
.......*....*
.....*........*
.......*....*
........***

(That's suppose to be a ball...use your imagination.) Try to ignore the dots. I had to use them as placeholders because the graphic collapsed (spaces eliminated) when I posted.


.........^
.........|
.......***
......*.^.*
---*...|...*---
......*....*
.......***


The carot and the line at the top symbolize an arrow indicating the direction the ball is traveling down the lane. (Remember, we're viewing from the top.) The arrow inside the graphic indicates the direction the ball is rotating. The three hyphens on either side indicate the axis about which the ball is rotating. Since it is traveling in the same direction it is rotating, we have 0 degree axis rotation.

As you concluded, this would be a ball released with the hand fully behind and up the ball.


.........^
.........|
.........|
.........|
.........|
.......***
......*....*
.....*..<-..*
......*....*
.......***
.........|
.........|
.........|

Same direction of travel, but the ball is skidding. The direction the ball is rotating is 90 degress from the direction of travel as indicated by the arrow inside the ball. Again, the three dashed lines symbolize the axis on which the ball is rotating as viewed from the top.

This would be the 'cranker' release. As you noted, with the release effort focused on the side of the ball.


................/
.........^..../
.........|.../
.......***
......*....*
.....*..\...*
......*....*
.......***
....../
...../
..../

Hopefully you have guessed from this really ugly graphic, this is a 45 degree axis of rotation. The slash in the ball is the direction the ball is rotating. I couldn't put an arrowhead on it because there is nothing on the keyboard that looks like a 45 degree arrowhead.

AXIS TILT:

For axis tilt, we lay down on the approach and look at the back of the ball as it travels away from us:


.......***
......*.|.*
---*...|..*---
......*.|.*
.......***

Again, the three hypens on either side of the ball indicate the axis about which the ball is rotating, but viewed from the rear. In this case the axis of rotation is horizontal with respect to the lane. That would be zero degree axis tilt. The three lines inside the ball symbolize the oil line or 'Track' of the ball. The Track would essentially be dividing the ball in half for a zero degree axis tilt.


................/
............../
............./
.......***
......*\...*
.....*..\...*
......*..\.*
.......***
....../
...../
..../

The three slashes outside of the ball graphic is the axis about which the ball is rotating. Since we are viewing the ball from the rear, the axis is tilted 45 degrees. The lines inside the ball poorly represent the ball Track. The Track would actually be about halfway between the lower axis point and the center of rotation of the ball. In other words, the more axis tilt, the smaller the Track as it gets closer to the axis point.


.........|
.........|
.........|
.......***
......*....*
.....*......*
......*....*
.......***
.........|
.........|
.........|

This is the 'helicopter'. The axis of rotation is perpendicular to the lane. For explanation purposes, there is no Track because the ball is spinning about the contact point on the lane.

Hope this helps,

</font><blockquote><font size="1" face="VERDANA,ARIAL,HELVETICA,TAHOMA">quote:</font><hr /><font size="2" face="VERDANA,ARIAL,HELVETICA,TAHOMA">Originally posted by Coachrich:
Hi Maf south,

Let me give it a shot... </font><hr /></blockquote><font size="2" face="VERDANA,ARIAL,HELVETICA,TAHOMA">Rich...Excellent way to describe rotation and tilt. This is a very hard thing for most bowlers to understand and the visual along with the words made it much better. Great work...

See ya in a few days...

Dan

:rolleyes: :rolleyes: :rolleyes:

coachrich, thank you very much for your illustruation particularly on axis tilt even though I still not 100% understand. I'll try to read more books to get it right.

Coach Rich, First let me say applause for your
drawing of the axis tilt and axis rotation. Next
I almost understand it. That amazes me. I don't
think I will use this cause there is enough doubt
in my mind to stay away. But what can be done with
a computer may not be able to be done with a bowling ball. You are better at what you do then
I thought. Keep up the good work.

SOME DAY I"LL THROW A 300 game
BOWLING JOEL

I understand the graphics. They were done well considering the medium here! Thanks a bunch!

But how do I determine what my axis of rotataion and tilt is? Heck I just try to get it down the lane where I can reasonably control it. Should I have someone watch me and guestimate or should I video tape myself from above and behind and try to measure it? Does anyone know how to get the most accurate measurement of these attributes of my roll?

Tblues,

You can see it by putting tape on your axis point and observing the tape as the ball travels down the lane.

After throwing the ball and retreiving it from the return, look for the oil ring. There may be several rings that intersect at two points depending upon how the ball was drilled for reaction.

Put the ball in an ashtray so that the ring is on the top half of the ball and level to the floor. If several rings, use the ring closest to the thumb hole.

The point at the top and bottom of the ball is your axis of rotation. Place a piece of white tape (white ball tape used to adjust hole size will do) at the very top of the ball.

When you throw the ball, you will should see the tape as a solid spinning dot. If it looks like a small ring, you may need to adjust the tape position until you find the axis point.

If the ball had several rings, the tape should look like a solid dot, then begin to 'wobble'. This is called axis migration and is evident on balls drilled for more reaction on the back end.

If the dot is spinning parallel to the lane and pointed to the side wall of the bowling center you have zero degrees of axis tilt (dot parallel to the lane) and zero degress axis of rotation (dot pointed toward the wall).

As the dot is directed more toward the lane, the more axis tilt. As the dot is pointed more toward you, the greater the axis of rotation.

Hope this helps,

Thank you for the tip!! I remember a coach putting a round piece of tape on the outside of my Track when I was a teenager. When I shot, the tape seemed to stay on the left side, almost as if it were floating. But when my ball got farther down the lane, it began to move slightly towards me and to the ceiling. I'm going to try it now and see if I'm rolling it any different. I never thought it would help me find the angles of rotation and tilt, so I guess that's what my coach was looking for.