Two Seamers

[sluggers]

JJ:

I have this thing called a "job". And, when I do my "job", they give me $$$. When I post on this board saying that 11 YOA girls cannot throw a split finger fastball like a 26YOA MLB PRO, I don't get $$$. Generally, I opt for $$$.

Additionally, you now agree with me that the movement of the split finger fastball is based on the orientation of the axis and the spin rate as well as the seam orientation.

Therefore, I think you have to agree that your idea that 2S fastballs and 4S fastballs move differently is a pile of horse manure.

POBOY:

Your article is about a split finger fastball. As I understand it, you are suggesting that the movement of the *SPLIT FINGER FASTBALL* is due to three factors: (a) orientation of the axis, (b) spin rate and (c) seam orientation. You have not proven anything yet, but are suggesting a theoretical basis for explaining the observed motion. (I also understand that your article is not intended for scholarly consumption, so I won't nitpick it.)

Unforutnately, JJ and I aren't arguing about split finger fastball vs. 4S fastballs. We are arguing whether 2S fastballs and 4S fastballs have different movement. I referenced a couple of studies showing that movement of the 2S fastball and 4S fastball were the same. I don't believe you are saying anything about 2S vs. 4S fastballs.

JJ, of course, prefers to argue about whether a split finger fastball moves differently than a 4S fastball (it does) rather than argue about whether a 2S fastball moves differently than a 4S fastball (it does not). You have absolutely ZERO evidence otherwise.

 

[JJsqueeze]

Aren't moderators supposed to avoid pointing out that wasting time on this site makes you less productive at work? Luckily as a self employed individual I get to make money while wasting time on this site by bouncing back and forth between my remote connection to my servers and my umbilical chord to this forum....but I digress..

I do not think we are arguing by the way. I feel more like I am slowly unravelling the bandages over your eyes but it has to be done slowly so the light does not blind you.

Additionally, you now agree with me that the movement of the split finger fastball is based on the orientation of the axis and the spin rate as well as the seam orientation.

Since that is so, I think you have to agree that your idea that 2S fastballs and 4S fastballs move differently is a pile of horse manure.

This is the foundation of your misunderstanding. I am really not talking about grip at all so lets forget 2 seam/4 seam/split finger etc for a moment and just talk about how the ball is travelling in relationship to the wind.

What I am saying, and all I am saying is that when you have a spin that is rotating with mostly 4 seams in the wind then you will get breaking motion based on a magnus force. This force will be in the direction of the rotation as seen from the front (winward) side of the ball. So a ball with the front rotating down will break down, to the left with break left etc...

When you have a ball travelling in such a way that you can get the largest possible difference in surface roughness (and therefore turbulence) between the two sides, then the ball will break using a different mechanism than the magnus force) this force will act at like a finger being pushed on the smooth side. So it breaks away from the smooth side.

The only reason I used the 4 seam v 2 seam naming is because when you grip a ball in these ways you generally (respectively) get the effects noted above more easily. But once again this is ALL ABOUT GETTING A SMOOTH SURFACE ON ONE SIDE AND A ROUGH SURFACE ON THE OTHER FOR WHAT I AM CALLING A 2 SEAM EFFECT...

So lets stop the straw man arguments and get on the same page. We are not talking about straight fastball perfectly aligned vertically and horizontally and simply switching from 2 to 4 seams, we never were. We are talking about how you can vary the axis to create this surface variance and throw pitches that break due to this effect and NOT BECAUSE OF SPIN!!!! Repeat after me...NOT BECAUSE OF SPIN!!! So while you can throw a ball that curves away from a RHB using a spin where the leading edge is spinning in that direction, you can also curve a ball that direction by having backwards or forward 12-6 spin that is slightly off axis.

As for the horse manure, at this point where there are a bunch of people with varying levels of experience reporting the exact same thing, physicists from two hemispheres reporting the same findings, major league pitchers in agreement as well, even someone as stubborn as you (not a bad trait in my book) has to admit that maybe they are on a sinking ship logically. A two seam fastball WILL move differently than a 4 seam fastball for any given spin axis and rate. The effect is minimal when it is straight 12-6 spin perfectly aligned to the wind though.

hope the light doesn't hurt too much boss....

 

[BuckeyeGuy]

JJ, you are confusing the hell out of me.

When I hear/read "2-seam", I envision a ball rotating about an axis such that the place where the seams are closest together is traveling around the axis at the highest rate at what could be called the equator of the ball. I am the world's worst artist, but my brain sees this:


Is this what you guys are talking about?

 

[JJsqueeze]

Buckeye-

Basically yes, but remove the "highest rate possible" as the effect we are discussing is not caused by spin rate and make the front of the ball slightly off center so that the wind is "seeing" a rough surface (mostly seam) on one side and mostly a smooth spot on the other side. Below is an image taken from one of the papers referenced. You can see that one side of the ball (with the dashed circle) has the wind interacting with a bald spot, the other side is interacting with mostly seams (not shown but easy to visualize the seams). The pitch this paper is based on was not rotating fast at all but broke a large amount.

 

[riseball]

JJ, you are confusing the hell out of me.

When I hear/read "2-seam", I envision a ball rotating about an axis such that the place where the seams are closest together is traveling around the axis at the highest rate at what could be called the equator of the ball. I am the world's worst artist, but my brain sees this:
View attachment 7633


Is this what you guys are talking about?

Add some yaw per JJs cartoons and you have it. It is the yaw that orients the seams resulting in movement. No yaw and it runs fast, flat, and fat.

 

[BuckeyeGuy]

Finally an image!

OK, which direction is the ball travelling there?

 

[JJsqueeze]

Finally an image!

OK, which direction is the ball travelling there?

It is breaking away from a right handed batter the image is drawn from the catchers perspective....look back at the post with the Freddy Garcia pitch, this image is taken from a paper describing the reason it broke. There is a fairly detailed explanation in the paper describing what is going on.

 

[riseball]

This is a baseball pitch but for softball purposes I think you need to look at the pictures as though it was the pitchers perspective.

 

[riseball]

RANDOM THOUGHT - The people who back in the day designed the current stitching pattern for baseball/softball could not have known how it would influence the game.

 

[sluggers]

I understand the phyisics described in Dr. Nathan's article. I'm not sure you do.

We are not talking about straight fastball perfectly aligned vertically and horizontally and simply switching from 2 to 4 seams, we never were.

Yes, we were. When you realized you were wrong, now you say, "Well, there is more to getting ball movement than simply changing from 2S to 4S."

But, then you contradict that statement by this:

The effect is minimal when it is straight 12-6 spin perfectly aligned to the wind though. A two seam fastball WILL move differently than a 4 seam fastball for any given spin axis and rate.

??? How are those two statement consistent?

You might want to consider this:

Watts and Ferrer measured the lift force on spinning baseballs in three different orientations and found that the orientation had no effect. They concluded that a spinning baseball behaves as a fully rough sphere regardless of where the seams are located.

That is what Rod Cross said in the article that *you* and Poboy both cite. They were referencing the article R.G.Watts and R. Ferrer, "The lateral force on a spinning sphere: Aerodynamics of a curveball," Am. J. Phys. 55, 40--44 (1987). Dr. Nathan has cited the same article in some of his papers.

NOT BECAUSE OF SPIN!!!! Repeat after me...NOT BECAUSE OF SPIN!!!

Either (a) you don't understand or (b) you type without thinking. Spin is critical, according to Dr. Nathan.

The physics are this:

The area around one pole of the spin axis is devoid of seams when the ball spins. This area is "smooth". The other portion is "rough" because of the spinning of the ball and because the seams are in that area. This causes the ball to move. (That is Dr. Nathan's theory. It is interesting and, if valid, would explain the movement of split finger fastballs.)

As for the horse manure, at this point where there are a bunch of people with varying levels of experience reporting the exact same thing, physicists from two hemispheres reporting the same findings, major league pitchers in agreement as well, even someone as stubborn as you (not a bad trait in my book) has to admit that maybe they are on a sinking ship logically

Please share what you are smoking.

The lay people are saying the ball breaks inside, outside, up, and down.

Dr. Nathan proposed a theory as to why the split fingered fastball moved.

Dr. Cross said this:

When thrown as a 2seam or 4-seam fastball (in terms of its orientation rather than speed) the ball did not deflect sideways since the seam remained symmetrical in the y direction.

(page 19).

That much blows apart your entire argument.