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Author Topic: Layout ? from Ebonite  (Read 727 times)

qstick777

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Layout ? from Ebonite
« on: July 26, 2007, 08:31:09 AM »
I was watching the videos under the NVS ball info (http://www.ebonite.com/products/detailnvs.php?PRKey=273) and they have some videos about locating PAP and laying out a ball.

They have one where they have the following steps:
1) draw line from pin to MB;
2) measure 2 inches to right of MB and make a mark;
3) measure 3 inches to right of pin and make a mark;
4) connect the two marks and this becomes the VAL;
5) measure [desired distance] from pin to the VAL and this becomes the bowlers PAP;
6) measure backwards from PAP to find grip center, etc, etc.

In another layout they measure 1 1/2" from MB and 2" from pin to create the VAL.

Is this based on the desired layout?  How do you know how far to measure from MB and pin to create the VAL?  Is there some sort of set formula, or can you just randomly choose distances?

I understand the usual 4x4 (and to some extent the degree system) for laying out balls, but I've never seen where you can measure certain distances from MB or pin to locate the VAL.

Can anybody explain?
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shelley

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Re: Layout ? from Ebonite
« Reply #1 on: July 26, 2007, 04:47:44 PM »
Yes, it is based on the desired layout.  Different measurements will create different PAP-pin-MB angles.  Since you need a third measurement beyond pin-to-PAP and MB-to-PAP (or PAP-pin-MB angle) to nail down a layout, they're using pin-to-VAL, which Storm and Morich also use.  You could also use pin height above the midline.

That system seems confusing to me because, like you, I'm used to pin-to-PAP/MB-to-PAP and pin-to-PAP/PAP-pin-MB angles, but it will do the same job.  I would not know how to relate pin-to-VAL and MB-to-VAL to the usual 4x4-type layouts and angle-based layouts without more experience.  

It's just another layout system, in the end they're all simply theoretical models that sort of fit experimental data for various pin/MB locations.  The 4x4-system might fit the data better in one place than another, the angle based system might fit it a little differently.  You're trying to predict what the ball will do using those models and they all have their strengths and weaknesses while trying to account for the zillion extra variables that you have very little control over (speed, rev rate, rotation, tilt, the oil pattern as it's laid down, the lane topography,...).

SH

jgreenwd

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Re: Layout ? from Ebonite
« Reply #2 on: July 26, 2007, 05:05:30 PM »
Similar to what Shelley said, it appears to be a modified version of the "pin buffer" system from Storm. There are 2 key differences: 1.) they are referencing the MB from the VAL, instead of from the PAP; 2.) they aren't scribing an arc from the pin or MB (which means that those reference marks they're using have potentially huge margins of error in placement).

qstick777

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Re: Layout ? from Ebonite
« Reply #3 on: July 26, 2007, 06:13:38 PM »
Do they get the 2" from MB and 3" from Pin numbers based on the known PAP of the bowler?

I'm confused over how they pick those numbers, as 3" (pin) and 2" (MB) gives a different VAL versus 2" (pin) and 1.5" (MB), in terms of the pin to MB angle (for lack of a better term).


Does any of what I'm asking make sense?  A bowler with a PAP of 4 1/2 x 1/2 up will fall in a different spot on the drawn VAL than a bowler with 5 1/2 x 3/4 up.  

So why the differences in the distances?  Is there some formula or chart that says that 3" from pin and 2" from MB will give you a 75* layout (or whatever it is)?  That would be helpful since I don't have a pro-sect scale to give me the built in degrees and angles.


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shelley

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Re: Layout ? from Ebonite
« Reply #4 on: July 26, 2007, 07:08:22 PM »
No, the PAP is determined from the layout, and the center of grip is backed out of that.  The chosen layout has the pin 2" from the VAL and MB 3".  Then the pin-to-PAP length is decided (usually you choose that first).  A circle around the pin that's, say, 4", will intersect that VAL line somewhere (well, two places, but only one will make sense).  Since the VAL passes through the PAP, where those the 4" arc and the VAL meet must be the PAP.

From there, your midline is perpendicular to the VAL through the PAP.  Measure 4 1/2" over (from your example PAP) to find the centerline.  1/2" up from that is the center of grip.

The layout determines the point on the ball that you call the PAP.  How you choose the layout is up to you: Ebonite's pin-to-VAL and MB-to-VAL, Brunswick's pin-to-PAP and PAP-pin-MB angle, or the traditional pin-to-PAP and MB-to-PAP system.

Those layout systems will give you the PAP.  From there you back out the center of grip.

SH

qstick777

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Re: Layout ? from Ebonite
« Reply #5 on: July 27, 2007, 12:38:35 PM »
Okay, I guess that makes sense.  

I just don't see anything in the Ebonite drilling instructions that make reference to pin-VAL or MB-VAL distances.  I do see those references in the Storm drillings, but not Ebonite.  

I'm used to the pin-PAP, CG-PAP, and MB-PAP references and drawing the arcs, picking a distance above mid-line and then backing the measurements to get grip center.

It probably would have made more sense to me yesterday if I didn't have a migraine and wasn't going through caffine withdrawl.

Thanks for the clarification Shelley, and jgreenwd thanks for reminding me about the Storm system (I downloaded that earlier but lost it when my hard drive crashed last week).
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