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Drill angle and ball motion

Posted: February 23rd, 2018, 7:00 pm
by Jmc1972
Studying drill angles and hoping to get some help in understanding...

I’m trying to figure out how to determine different degrees determine different length of skid. So to help me understand this a little more with all else being equal-

Same Ball
Same bowler metrics
Same Pin to PAP
Same VAL

What would be the difference seen in ball motion for a ball with a Drill Angle of:

40* -

45* -

50* -

55* -

60* -

And how does the Pin to PAP and VAL change this?

I’ve been studying for a while now and after trying to learn it all at once I’ve decide to try and tack each of the 3 once section at a time.

Thanks!

Re: Drill angle and ball motion

Posted: February 23rd, 2018, 8:54 pm
by TonyPR
This is where I learned it:

http://above180.com/category/ball-drill ... es-series/" onclick="window.open(this.href);return false;

Start with part 1 at the bottom of the page

In general, the closest the PSA is from the RG of your PAP the shorter the distance the axis has to migrate to cross the pin to PSA line the earlier the reaction will be so, the smaller the drilling angle the faster the first transition (from skid to hook) will be.

Re: Drill angle and ball motion

Posted: February 24th, 2018, 2:48 pm
by Jmc1972
TonyPR wrote:This is where I learned it:

http://above180.com/category/ball-drill ... es-series/" onclick="window.open(this.href);return false;

Start with part 1 at the bottom of the page

In general, the closest the PSA is from the RG of your PAP the shorter the distance the axis has to migrate to cross the pin to PSA line the earlier the reaction will be so, the smaller the drilling angle the faster the first transition (from skid to hook) will be.
Thank you!

Realizing I’ve been looking at it completely wrong.

Re: Drill angle and ball motion

Posted: February 24th, 2018, 10:13 pm
by JohnP
Keep in mind that the drill angle is meaningful only for asymmetric balls. With a symmetric ball the psa after drilling will always be located near the thumb hole (best estimate without using a Determinator is 1/2" left of the thumb hole* and 6 3/4" from the pin) unless a balance hole is used. -- JohnP

*for a right handed bowler

Re: Drill angle and ball motion

Posted: February 28th, 2018, 8:29 pm
by Arkansas
You might want to have a look at this.
http://wiki.bowlingchat.net/wiki/index. ... lained.pdf" onclick="window.open(this.href);return false;

Re: Drill angle and ball motion

Posted: February 28th, 2018, 9:00 pm
by stevespo
My first thought was -

Can anybody with Blueprint simulate this and quantify the differences?
Can you run the numbers on a strong asym vs. a weak asym? Does that matter?

My second thought was -

We're confident the smaller drill angles will transition sooner, so does the amount really matter? Surface prep is going to have a greater effect than a 5, 10 or 20 degree change in drill angle...

Last thought -

It would be interesting to compare the results from the Blueprint drill angle simulations with those from a consistent drill angle using only surface prep to get the transition points reasonably close.

How does the rest of the shape compare when you're using layout vs. surface?

Steve

Re: Drill angle and ball motion

Posted: March 1st, 2018, 3:49 pm
by Arkansas
https://www.bowlingthismonth.com/bowlin ... ll-motion/" onclick="window.open(this.href);return false;

Re: Drill angle and ball motion

Posted: March 1st, 2018, 4:36 pm
by stevespo
Yes, good article. By changing the Pin to PAP from 3, 4, to 5" the ball position at the pocket was still within a 1/2 inch. Even varying from 2 to 6 inches, the pocket position was within roughly 1.25 inch.

Pin position changes are not the same as drill angle changes (DA and VAL remain constant with changes in pin distance) but it's still interesting. Every 10 degree change in drill angle will shift the PSA 0.75 inch. Regardless, I'd expect a similar (relatively small) amount of change in ball motion going from 40 to 50 to 60 degrees. I was just hoping to quantify it...

"If nothing else, I hope this article will convince some people that—at least in most “normal” situations—tiny differences in layout do not cause gigantic differences in ball motion. Every minute you waste stressing out about small and insignificant differences in your layouts is a minute you’ll never get back. There are more important things in bowling to worry about, so spend that time worrying about them instead."

I agree.

Steve