Mo Fact Sheet
These are some quick facts posted by mo on various parts of the forum.
- For low tilt bowlers, on asyms., use pin to PAP distances of 2 3/4" to 4" to get the ball to change direction and read friction. Use 4" to 5" pin to PAP distances when you want to play straighter.
- For high tilt bowlers, don't use 3" to 4" pin to PAPs on asyms. unless there's lots of friction, or you're using a ton of surface with a big, strong balance hole. Use 4" to 5" pin to PAPs to read friction and 5" to 6" pin to PAPs to play straight. Another example of the need for accurate delivery specs.
- In reality, the coverstock, surface sanding, ball total diff., and pin to PAP distance control the length of the first transition. The layout and balance hole location, which affect the strength of the PSA affect the distance from the first transition to the second transition. That's basically the intermediate diff. of the drilled ball.
The smaller VAL angle increases both diffs., but it increases the intermediate diff. much more than it increases the total diff., thereby increasing the diff. ratio. The smaller diff. ratio causes the longer hook zone (slower transition).
Lowering the pin towards the midline lowers both diffs., but lowers the intermediate more than the total diff., thereby decreasing the diff. ratio.
60x20 to 60x50 is a big change. I usually make 10* changes. P4 balance holes change diffs. more than small angle changes. Try to get it a close as possible with the layout and, then, tweak it with the balance hole. That's the best system.
(For symmetrical balls): You're getting pretty good. Put the balance hole on the VAL 2" below the midline, if needed. Drill it 2 3/4" deep. As you make it bigger, it will pull the PSA towards it and reduce the drilling angle to get the ball to start up a little sooner.
For balance holes close to the thumb hole: The pitch of the balance hole plus the distance that the center of the hole is from the edge of the thumb assembly must equal 2 1/2" plus whatever lateral pitch toward the balance hole the thumb hole has. Voila!
When the fingers are over 3" deep, don't go any deeper than 2 3/4" on the balance hole! The holes will meet, if you drill the balance hole too deep.
Staying behind the ball causes it to track high. Specifically, lack of axis tilt. Staying in the thumb too long causes it to track very close to the thumb. That's the real skinny.
Reply to a two handed bowler who was clipping the edge of his thumb hole: Stop chasing your tail! Let's adjust your finger pitches since you don't use your thumb. Drill your fingers 7/16" left by 1/4" forward on your middle finger and 7/16" right by 3/8" reverse on your ring finger, if you're right handed. Now measure your initial axis tilt and your PAP and post that info. We'll go from there. No more hand grenades at 20 paces! Use your normal thumb hole location.
- This quote taken from http://forum.bowlingchat.net/viewtopic.php?f=6&t=4557&p=36474#p36474 (see # 19)
ALL bowling balls with migrate along the RG contour of the Bowler's PAP. That's governed by the laws of the universe. Therefore, in order to create a unique migration path, you must create a unique RG contour for that ball. ALL balls have RG contours that use the low and high RG axis as the centroid for the RG contours. The higher the differential ratio, the more of the RG contours that are centered around the high RG axis, and the flatter those ellipses. That's just pure science and math.
- Don't worry about the cg. No problem. CGs don't mean a thing (to) ball motion as long as the ball has legal statics. .... NEVER put balance holes below the thumb. Too much of a chance of flaring over it.
*With Scotch Brite pads, it's all about the pressure you use with the pad. Burgundy results in 400 to 800 depending on the pressure. Grey results in 800 to 1500, again, depending on the pressure used.
Using scuff pads is not an exact science, but this is usually done during practice when the ball you want to use is not reacting enough. After the bowling is done, I always recommend using a spinner to return the ball to its' normal surface.
On a symmetrical ball drilled without a balance hole, the PSA (high RG) axis ends up very near the thumb. That puts the PAP near the intermediate RG axis on a vast majority of bowlers. Putting a balance hole in the PAP, which is near the int. RG axis, raises the RG of the int. RG axis. That decreases the int. diff., which makes the ball more symmetrical. That's what blueprint's excellent attachment shows. This explanation is for those who have math phobia.
Increasing the reverse in the middle finger actually helped to lower your tilt. Changing pitches changes the resulting ball motion. If you have to change the grip to accomodate issues like this, CHANGE THE SPAN FIRST TO RELIEVE THE PRESSURE, NOT THE PITCH, UNLESS YOU WANT TO CHANGE THE ROLL!
Sand 4 ways thoroughly with the first grit and sand two ways quickly with the second grit to do the "skip a grit" procedure.
Stretching spans tends to decrease tilt as does reverse in the fingers.
- Reply to a two handed bowler who was clipping the edge of his thumb hole, from http://forum.bowlingchat.net/viewtopic.php?f=7&t=4798
Stop chasing your tail! Let's adjust your finger pitches since you don't use your thumb. Drill your fingers 7/16" left by 1/4" forward on your middle finger and 7/16" right by 3/8" reverse on your ring finger, if you're right handed. Now measure your initial axis tilt and your PAP and post that info. We'll go from there. No more hand grenades at 20 paces! Use your normal thumb hole location.
Why is it that Mo doesn't recommend pin to pap distances of anything past 5.5 ?
Here's the real reason. The low RG axis can move when the ball is drilled. Using a pin to PAP distance of > 5.5" might result in the real low RG axis moving to a pin to PAP distance > 6 3/4". That may cause the ball to flare in bad places, causing the ball to flare over some drilling holes. NOT GOOD!
I'll try to make this plain. All balls are delivered with more axis rotation than tilt. Cannot be any other way. The laws of physics dictate that. The ball loses both rotation and tilt. The ball loses rotation faster than it loses tilt until tilt = rotation. That occurs at the second transition. FACT! During the roll phase (after the second transition) the ball loses rotation and tilt at the same rate until the ball hits the pins. That should keep your mind busy for a while.
Phasing is a function of porosity. Change in temperature causes it to absorb moisture. I light wipe with a little acetone, or a hair dryer will get rid of it. BALLS THAT PHASE EASILY HOOK!
This is what a vast majority of low tilt players don't understand. This is the magic. Fingers on the inside hemisphere of the ball at the top of the swing. Fingers move across the back of the ball until the hand reaches the "Nike Swoosh" position at the end of the follow thru. If the wrist is cupped at the top of the swing, it MUST be unloaded by the time of the release.
The reason we use a higher angle ratio for symmetrical balls is that drilled symmetrical balls lose tilt at a rate almost double the rate that asymmetrical balls lose tilt as both types of balls go down the lane.
You're very close. With a symmetrical ball, the PSA will be very near the thumb hole after drilling until the balance hole is drilled. We can change the mass properties of the drilled ball about 40% with layout and balance hole. With an asymmetrical ball, we can put the PSA whereever we want, and change the mass properties of the drilled ball by as much as 84% with layout and balance hole.
Conclusion: Syms are easier to drill and less versatile, making ball selection a premium. Asyms are more versatile and can provide stronger motion, but are dependent on the skills of the ball driller because they are more sensitive to the layout and balance hole.
The higher the diff. ratio, the more the ball displays gyroscopic properties because the PSA is stronger with a higher diff. ratio. In fact, that will help it retain tilt longer. I've been measuring it for years and syms lose tilt about twice as fast as stronger asyms.
The ability of the ball to retain tilt is related to the strength of its' PSA.
Blueprint has done a great service here. the difference is instantaneous direction as opposed to a fixed point rotation is measured against. Since the bulk of my research is from a fixed camera position, this difference can occur. Very educational!
Axis tilt is in relation to the horizon, so it's the same in either system. True "roll out" occurs when the ball has 0* instantaneous axis rotation and 0* of axis tilt. Using Blueprint's system of measuring axis rotation, a ball stops hooking when the instantaneous axis rotation is 0*, the second transition! the ball will have effective hitting power as long as it still has axis tilt. The ball stops hitting when axis tilt reaches 0*.
Good work, Blueprint!
Q. Just wondering if using p3 and p4 balance holes for low tilt players could cause the ball to lose tilt too quickly because of the increase in differential/flare, the same way as using max flare pin postions does. Should there be any concerns? Thanks.
A. Unless they're strongly speed dominant, be cautious with strong balance holes for low tilt bowlers.
- This one is from Elgavichon, from: viewtopic.php?f=15&t=4992
The PSA on symmetrical cored ball without a balance hole ends up 6 3/4" from the low RG axis (primary pin), within 1/2" of the centerline of the grip.
- From: viewtopic.php?f=15&t=4735
Your discussion of the movement explains why the "flare safe" zone, that I've recommended for two decades, goes from pin to PAP distances of 3/4" to 6 1/4". After seeing that the low RG axis can move as much as .6", I'm now going to reduce the flare safe pin to PAP distances to 3/4" to 6". I use 5 3/4" as my max. pin to PAP distance on the balls I personally layout. Balance holes near the high RG axis can be,and are, extremely effective, but balance hole near the intermediate, or low, RG axis can be dangerous because of the movement they can cause in ALL of the primary axis. I've do have some ancient engineering training, but have had to use empirical research to develop most of the techniques that I recommend and teach. Thanks for confirming that I didn't waste my time.
On a symmetrical ball drilled without a balance hole, the PSA (high RG) axis ends up very near the thumb. That puts the PAP near the intermediate RG axis on a vast majority of bowlers. Putting a balance hole in the PAP, which is near the int. RG axis, raises the RG of the int. RG axis. That decreases the int. diff., which makes the ball more symmetrical. That's what blueprint's excellent attachment shows. This explanation is for those who have math phobia.
The problem is simple!!!!!! This is a good time to address the cause, since you've asked. GOOD BALL REACTION OCCURS WHEN A BALL IS ROLLED IN ONE DIRECTION AND ROTATED IN ANOTHER! THE ANGLE BETWEEN THE DIRECTION OF TRAVEL AND THE DIRECTION OF ROTATION IS MEASURED IN TERMS OF AXIS TILT AND AXIS ROTATION! NOT ENOUGH OF EITHER AND THERE'S NOT ENOUGH BALL REACTION! As the ball travels down the lane the forces of gravity and friction reduces those angles. As those angles are reduced, the ball tracks higher. When it tracks too high, it hits holes.
Q. When laying out balls for specific conditions (long/heavy/short/dry) is it best to adjust ratios or sums (or a combination of both)? What range (in terms of ratio changes or sums) are generally useful, and how bowler specific is this? I guess I'm trying to get a handle on how far from the benchmark ratios/sums it is safe to venture when laying out balls for specific conditions.
A. You adjust the sum of the angles to move the transitions on the lane. You adjust the ratio to change the shape of the ball motion. You adjust the pin to PAP distance to mainly control the flare, which strongly adjusts the distance of the first transition.
Q. But my original question still remains: what is the reason why we keep ratios the same when looking to delay the first transition with a (close to) identical hook shape? Are the ratios themselves affecting the ball motion? Or are they a useful tool to manage more difficult to measure variables?
If the second, how does a ratio change affect the variables (perhaps the differentials)? Why is a change in drilling angle not preferable to a change in both angles?
A. Either one is useful. Changing the drilling angle delays the first transition and leaves the second transition the same distance from the new first transition. Changing both angle delays the first transition and increases the distance from the first transition to the second transition. This keeps the proportions the same (for example, 20ft first transition, 10ft hook zone becomes 25 ft first transition, 12.5' hook zone).
Sounds like your fit is close. My check, as always, is to place your fingers in the finger holes and, then, place your thumb ALL the way into the thumb hole by pressing down on the back of the knuckle above the thumb. If your finger nails press against the back of non Vacu inserts, your span is too long on either finger you feel the pressure on. Vacu grips, as traditionally done, allow too much movement for the fingers in the inserts IMO.
To allow for swelling, drill a hole 1/32" larger than the hole for the insert 1" deep (3/4" deep for short finger tips) at the cut span distance, then change the bit to the correct size for the insert and flush the bit against the front wall of the hole and drill it the desired depth. This will allow for the knuckle to swell and still keep the tip of the finger at the correct place at the bottom of the hole. I call these fake Vacu grips.
- Taken from context: viewtopic.php?f=13&t=431
For Asymmetrical balls:
For bowlers that come up the back, I prefer to use pin to PAP distances of 3" to 5". Closer to 3", if I want them to cover boards. Closer to 5", if i want them to play parallel.
- From: viewtopic.php?f=15&t=5119
Your very accurate! You must use balance holes to get true smaller drilling angles in symmetrical balls. What you've proved is that symmetricals transition very similar unless you use a balance hole. Use balance holes on the VAL below the midline to decrease the drilling angle. Use balance holes on the Gradient Line to alter the diffs. of the drilled ball to change the intensity of the ball reaction.
"For bowlers who get around the ball, I prefer to use pin to PAP distances of 4" to 6". Closer to 4", if I want them to cover boards. Closer to 6", if i want them to play parallel."
Q. Is it possible to lay out a ball to lower or raise the track of a bowler?
A. Not consistently, or effectively. Changing the track is related to changing the release, not the layout. Sorry!
Drilled asyms maintain their PSAs pretty well. Symmetrical balls end up with the PSA near the thumb, no matter where the cg is. Drilling the balance hole on the Gradient Line changes the intensity of the ball reaction on all balls. Balance holes on the VAL, below the midline, is the only way to reduce the drilling angle on a symmetrical ball.
- From: viewtopic.php?f=15&t=5222
Densities, my man. Inner cores average 2.6 g/cc, outer cores average 0.9 g/cc, coverstock is 1.10 g/cc.
