BallReviews
General Category => Drilling & Layouts => Topic started by: tgknukem on February 20, 2014, 04:15:26 AM
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In the 'Basic Top Weight Question' thread, it appears it was generally agreed upon that static weights have minimal to no effect on ball performance. If this is the case then how does drilling a ball 'pin up' vs. 'pin down' affect ball motion? Having the pin above the fingers or below does not affect radius of gyration, the only affects would be on the location of the bowties and static weights(i.e. finger or thumb weight). The ending static weights would also be dependent upon pin to CG distance and weight removal during drilling. I'm not aware of any way that drilling a ball 'pin down' can make it 'early revving' unless the final statics are thumbweighted, or if the pin is less than 3 3/8 inches from the PAP and 'pin down'.
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Height of the pin will affect the diff of a ball after drilling. A higher pin will have a higher differential which makes it transition faster in the backend....
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How physically does placing the pin 'up' vs. 'down' change Radius of Gyration Differential, and to what amount would this effect be? RG Differential is the difference between the RG of the ball with the core parallel the one's axis vs. the RG of the ball with the core perpendicular to ones axis. This difference is manufactured into the ball, and other than drilling holes into the ball I don't see how this difference can be changed.
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Hard to explain without a lot of physics. It has to do with how you start the ball rolling (your PAP) vs. how the ball wants to roll. Where you put the pin, compared to how you roll it determines the 'dynamic differential' and how it will react.
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I think a better way to look at this is:
1. Look at all aspects of a bowling ball before drilling. Mainly, look at the core and see its orientation in the ball.
2. Look at the core numbers to get an idea of how much affect the core may have on ball dynamics. (big core or little core, low RG or high RG, etc...)
3. Now, imagine drilling holes (pin up) in the ball and taking out chunks of the core. The core is more dense than any other part of the ball and changing its shape and mass will have the largest affect on ball dynamics.
4. Evaluate the ball with the holes in the ball and imagine the change in the core dynamics.
5. Go to step 3 and re-imagine with a different drilling (pin down). Repeat as much as necessary.
The thing to consider is the holes you are drilling into the ball change the core dynamics. I am sure everyone agrees the ball's core statistics are not the same after drilling. Depending on where you put the holes, how big the holes and how deep the holes will change the dynamics from either a little bit to a whole bunch.
The pin up drilling will take a little of the core at the top of the ball with the fingers (small holes drilled shallow) and more of the center of the core out with the larger and deeper thumb hole. This looks to me like it should "increase" the RG and thus make the ball lope and get down the lane better.
The pin down drilling will take a little of the core out at the top (fingers) and still more out at the top (thumb). This looks to me like it would "decrease" the RG and thus make the ball get in a roll earlier and react earlier on the lane.
This is how I look at it, right or wrong.
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Real basic for now. On my phone.
Pin up raises RG of ball because you are taking mass out of the side of the core, making it taller. Lower you put the pin, the lower you're making the RG because you're taking mass out of the top, making it shorter.
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As you move the low RG axis you also move the ending location of the high RG axis. The location of these two items in reference to your style and in reference to your PAP will affect the way a bowling ball core reacts. It will also depend on the balls coverstock and intended design.
From a core stand point alone the smaller the VAL angle the quicker the ball reacts to friction. The larger the angle the slower it will react to friction.
As many have stated when the pin is above the fingers or even parallel with the fingers both the fingers and the thumb are taking a lot of mass from one side of the ball. If the pin is down you are taking mass from the top of the core, but depending on the location you are actually taking mass from either side of the top of the core somewhat evenly. It will not be as affective of a removal as when the pin is even or above.
This affects the way the ball will flare on the lane and how it transitions from one phase to the next. Skid, hook, then roll. More or less skid, a longer hook phase, or a longer roll phase can all add up to a different reaction that we see or don't see on the lanes. The core with flare and how, and how much affect how the surface touches the lanes. The surface in combination with those aspects can be a big difference (high performance ball) or a very little difference. (lower or no performance ball)
These things are minimal in many cases when thrown on a THS. It can hide these things because of the oil volume and how the pattern literally shapes the ball on the lane.
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A pin up will take out more mass of the core near the high rg axis (which is 6 3/4" from the pin) than a pin down will. This will effectively raise the rg of the high rg axis which will create a bigger differential and also likely slightly raise the average rg. The low rg (Marked by the pin) isn't going to change too much because not a lot of the core is removed when drilling the fingers unless the fingers are drilled fairly deep. Of course there are other variables this is just a generalization from my understanding of what's happening.
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There are certain beliefs in ball motion that could easily fall into the irrelevant relevant category....static weights, pin up vs pin down, pearl vs solid...in a sense these have been simplified in regards to ball motion.
Static weights is obviously a horse that has been beaten to glue...
Pin up vs pin down should be also looked at in a simplistic manner - if you place a pin directly below or just above the gripping holes is there a true difference? NO - if you place a pin 1" below or 1" above the gripping holes is there a difference...???
Due to the densities of the cores and how they are manipulated to create top weight or pin outs are slight core shifts - 1/32" shift from true center if the mass to create a 1" pin out or 1oz of top weight....now take into consideration that each situation will or could result in differing amounts of mass when placing the gripping holes - inserts vs no inserts and actual size & depth of gripping holes. I know when I was still drilling professionally, we drilled the finger holes 2-2 1/8" deep and the thumb holes 2 5/8" deep to somewhat even out Thea's distribution. If we wanted to slightly alter the reaction we'd adjust the depths but how much is where the reaction is altered?
All of these things are a variable but truly at what point does it change? How much is visible over actual? How much is what we think over what is actually happening? I love drilling pins out a lot if times...what would that be? Pin up or pin down?
Trust me these factors are as much perception as it is reality...every situation can be deemed different in regards to the amt of built in friction side to side and front to back...
Make bowling simple...cover strength, surface prep and pin to pap to manage flare then add a weight hole to alter movement...if you like pin ups then by all means use them...much of the game is confidence...if you have confidence in a layout...use it!
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The biggest thing I took away from the book Head Games by JustRico was perception vs. reality. And this concept applies to a lot more than just bowling.
I also see a lot of bowlers who but more time & resources into their equipment and virtually nothing into their physical game. The layout of the ball is a small piece of the puzzle compared to everything that has to happen from the start of the approach to the ball hitting the pocket.
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Thanks Ric for the simple and realistic view. I kinda see this much like surface of the ball. Too many times people get caught up in the exact grit used on a ball. "I like everything at 2000!!!!" But in reality, every 2000 is different. If the ball is not transitioning early enough, go with a lower grit, if it is early, go with a higher grit. Simple. It may be good to have a general understanding of where you started and how you got to where you ended up, but don't get caught up in the exact numbers.
Bowling is an area where I feel you can be reactive and open to change instead of trying to be proactive and guess what is going to work.
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Not so fast!
Regards,
Luckylefty
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Rico,
Would saying that you can discern the static weights in the ball motion be akin to saying..."I can tell the difference in a fresh 2000 pad and one that has 1-2 uses"?
Not sure if this is an accurate comparison....
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I have a suburban and I removed the floor mats to go faster and get better gas mileage
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I have a suburban and I removed the floor mats to go faster and get better gas mileage
preception vs reality
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I'm not a balldriller, so I'll assume that some if not all of these explanations are correct. It' seems counterintuitive though to place a pin 5 inches from the PAP to decrease rev rate for control and then try to dig a bit of core out of the ball to increase rev rate, when one could buy a ball with a 5" pin and place the pin 1.75 inches from the PAP giving the same amount of axis migration and also giving a very noticable increase in rev rate.
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Rev rate is predicated by the bowlers attributes...not the bowling ball
Not exactly sure what you are trying to say
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There are certain beliefs in ball motion that could easily fall into the irrelevant relevant category....static weights, pin up vs pin down, pearl vs solid...
Static weights is obviously a horse that has been beaten to glue...
Pin up vs pin down should be also looked at in a simplistic manner - if you place a pin directly below or just above the gripping holes is there a true difference? NO - if you place a pin 1" below or 1" above the gripping holes is there a difference...???
I have to disagree with your assessment here. The majority of my equipment has always been drilled pin-up. A lot of my balls with the pin right over the middle finger. Here lately, I've been experimenting with pin-down layouts extensively, and for me, the pin-down layout is much more versatile, and useable on a variety of conditions.
I throw from 13.5- 15.5mph when bowling in most of my leagues. I have about a 350 rev rate, and am told that I have a lot of hand.
For me the pin-down drillings allow me to "hit it" or back-off as the condition requires, and I find that I throw a lot fewer splits now than ever before. Now mind you, the heaviest condition I throw on in any of the 4 leagues that I bowl, is a medium condition.
So to say that the change from pin-up to pin-down is imperceptible is not true to me. But, as in all things bowling, it depends primarily on the operator and the conditions he/she plays on. If I were playing on a heavy oil condition, I am pretty sure it would be much harder to read whether there was any change whatsoever.
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Did you replace the exact same balls that were pin up with pin downs? If you didn't you can't truly justify that statement
Trust me there is a lot to be said to what one thinks they see which if proper or correct to the eye increases one's ability to relax and perform...
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Did you replace the exact same balls that were pin up with pin downs? If you didn't you can't truly justify that statement
Trust me there is a lot to be said to what one thinks they see which if proper or correct to the eye increases one's ability to relax and perform...
Yes, I did. I previously had a pin-up Outlaw which I re-drilled to pin-down, and a pin-up Infinite Theory, re-drilled to pin-down. The Infinite is asymmetric and the Outlaw symmetric, I believe. Both of my new reactions are miles away from the original reactions I got from these balls. Both balls are much smoother, and break later. For me they are much more controllable.
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I tend to agree with Jesse James....I have two Nomads, both drilled with 5 inch pin to pap distances, one with a 40 val angle, one with a 70 val angle...same surface. I did this about a year ago when i was struggling. I had people tell me that because of my tilt, I would see a difference. I wanted to see for myself and also felt that in order to know I had to match two balls....so i did it....I do see a difference for me...and it is noticeable. Not that its night and day, but I do seem to find the pin down(70val) to be much more controlled and for me useable for longer periods of time. I even plugged my Pin up nomad to save for another day now.
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My Outlaw is 30x 5 x 70.
My Infinite is 20x 4.5 x 70.
Previously I could not use my Infinite in any of the houses I currently bowl in. It would read the mids strongly and make a huge move off the spot! This has now changed. I can now use it in all my houses, and just align my feet, while changing releases for desired amount of hitting power.
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Bowlers' attributes are not the only thing that determines rev rate. Rev rate of a spinning object is determined by rotational force(torque) applied, time amount torque is applied, and it's moment of inertia(expressed as units by radius of gyration for bowling balls-RG). Torque and time are bowlers attributes, Rg is a function of core design. The lower the RG measurement of a bowling ball-the more it's mass is located toward the axis, and consequently the easier it is for ones hand to spin it(apply angular momentum). A bowling ball is least difficult to spin with the core parallel to the axis-pin on the PAP, RG the lowest. A ball is most difficult to spin with the core perpendicular to the axis-pin 6.75 inches from the PAP, RG the highest. When 'hook' is solely a function of RG, then a ball with a pin 5" from the PAP will hook less then a ball with a pin 1.75' from the PAP because the rev rate is lower, it was more difficult to spin due to the RG being higher.
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Rev rate is solely and purely based upon the bowler and nothing else. You are referencing differing variables...RG is similar to an ice skater, if the ice skater's arm are closer to their body, they spin faster (low RG)...in the same sense, if the skater extends their arms, they slow their spin (high RG)...but the spin rate is still dependent on the ice skater's ability
Hook is any deviation from a straight line and predicated on more than merely the core dynamics and/or core numbers...for the core to have any effect on the reaction, the bowling ball has to slow down...this is (minus bowlers attributes) predicated by surface. If the bowlers ball speed is slower, the ball will tend to slow earlier and/or easier. If their ball speed is higher, the bowling ball, without proper amt of surface, will labor to slow down and struggle to change direction.
A bowler's ball speed dictates how the bowling ball will slow down...after that the rev rate, tilt & rotation dictate what the bowling ball will do at that point.
Bowling balls are merely tools of the bowler and should be used to compensate for what the bowlers lack and/or need in regards to reaction.
An object at rest remains at rest...no matter the RG or the diff until proper forces are applied plain & simple.
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I apologize for not being able to explain rotational mechanics in a way that you can understand. In the case of a skater you are referencing an object in which angular momentum has already been applied by her approach into the spin. Tucking her arms or extending change moment of inertia(RG), but do not decrease or increase initial force applied. Objects of the same mass but differing moments of inertia will spin at different rates if the same initial force is applied to them for the same unit of time, solely because of the differing radius of gyration.
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If you are under the assumption I am unaware of ball motion, ball reaction and/or what creates it...in abt 6 months (give or take) you can pick our next book in regards to this...thank you for thinking you are explaining, well not sure what you're trying to explain but you're off base in your assumptions...I am good in the world of physics and what is attributed to actually creating ball reaction.
One last thing, again rev rate is not predicated on a bowling ball or it's inherent core dynamics...it is solely based upon the bowler and their applied forces...bowling balls are tools or extensions of the bowler
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One guy is debating physics and the other practical application.
Here we go!
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which ball could you propel with a higher rev rate, a 10lb ball or a 16 lb ball, and why?
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I'm not debating physics...I'm stating the rev rate is solely predicated by a Bowler's attributes...the bowling ball & it's dynamics only enhance those attributes
He is stating physics in regards to the dynamics of the bowling ball
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Wait, you mean I can't get a bowling ball that will make me Jason Belmonte?
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Soooo, is a bowler's rev rate going to be calculated using a ball drilled on the high or low RG axis or are we going to diddle in the middle? And where do we find the person that is consistent enough for the couple of percent variance to make a difference?
Glad I didn't read about stuff like this when I still bowled. Would have been even harder to let it go than it already was.
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Pin up (lower VAL angle) use up the hook energy in a shorter, more sudden manner.
Pin down (higher VAL angle) spread this energy out over a longer area, more gradual.
This is due to the difference in initial rotation compared to where the ball wants to spin.
I'm getting the argument that a higher Rg layout (outside edge weight - think flywheel) is theoretically harder to get started spinning than a lower Rg layout (center heavy) - so maybe the bowler could put more revs on the lower Rg ball - but I'm just not sure that the difference in Rg is enough to give a measureable difference.
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I had now come to understand that the physics guys are wrong when they claim that the two physical properties of an object, it's mass, and the distance of it's moment of inertia from it's axis(radius of gyration), are variables in determining the rate at which I can spin it. The only variable in determining this is my bowler's attributes. I was both excited and apprehensive at what I was now going to do. My auto insurance adjuster was probably going to get pretty upset. I went out to my car and applied my bowlers attributes to it knowing that it's mass had nothing to do with me being able to spin it at 300 RPM, just like my Angle Evolution. I tried...zero RPMs. Tried harder...still zero RPMs. I stood there stunned and in disbelief. What to do now...I thought "put the pin below the fingers?" Then it hit me, the physics guys were right all along...mass of an object IS a variable for the rate at which I can spin it. A Mazda M3 hatchback is an object with physical properties just like an AMF Angle Evolution. So if the physics guys are right about the mass variable, I'm guessing they are right about the radius of gyration variable
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What's the RG of a Mazda?
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Dude I'm not exactly sure what you're trying to argue other than you have an understanding of physics...
So if you don't push the accelerator does the car go anywhere Mr Science guy? You're arguing semantics...
What's the potential of a bowling ball? If a car has a set rpm, it will go that fast no matter who is driving-no!
How much do you honestly believe a bowling ball will spin more in a 60' playing field? And if you have 150 rev rate vs a 400 rev rate the bowling ball will spin more relative to the applied forces but you still have 250 MORE rev rate...it's relative I'm not sure you get that
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I called Mazda. They said the minimum RG of a Mazda 3 hatchback is 2.51 and the maximum is 2.55, so it is withing USBC specifications. I didn't see it on the approved list for the PBA tour though.
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I went to Lowes last night and bought the biggest hammer they had. Suddenly, I became Thor. It was awesome! Best life altering tool ever!
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I know a guy who blew an engine in a Mazda 323 while bowling on the PBA Tour. Does that count?