Dual Angle Ratio Guide

'joint effort from Elgavachon/Athery'

ratio discussion

Mo once told us "Determine the ratio of the angles to determine the shape of the ball motion. Axis rotation and axis tilt affect this decision a lot."

Mo more recently said " Once you decide on the ratio, the rest is math". Here is a chart Athery has done to help with finding the RATIO and a RANGE OF RATIOS to do that math.

to obtain approximations of ratios (based off various of Mo's recommendations)

After you have calculated the total sums and before you can calculate the benchmark or sweet sums, it is necessary to find the benchmark ratio.

This is necessary To accurately calculate the drilling angle and the val angle individually. . The middle column (Initial Benchmark ratio) gives some examples of approximate ratios sometimes used by Mo for speed/revs matched + normal rotation. Please note: When doing the chart we used 50*-55* as normal rotation. (45* as slightly low and 60* as slightly high)

for tilts below 10*, please refer to chart at bottom of page for possible adjustments. (especially if low tilt is accompanied by higher rotation)

CHART IS BY ATHERY

speed or rev dominance and/or extreme high or low rotation

In case of a conflict between speed or revs and rotation, go with the ratios which correspond to the rotation.

You would adjust the #s based on the amount of dominance.

Extreme speed dominance and/or high rotation=decrease ratios.
(adjust to boxes further right on the chart)

Extreme rev dominance and/or low rotation= increase ratios.
(adjust to boxes further left on the chart)'

Mo very seldom gives an extremely large ratio range. It is more common with very low or very high tilt. A +or- of around .5 above or below benchmark ratio seems to be close to average ratio range.

RATIO RANGE

The drill angle determines the length of the slide phase of the balls motion. The val angle determines the length of the hook phase of the balls motion. The drill angle + val angle = the total length before the balls reaches the roll phase of the balls motion. The higher the ratio between the drill angle and the val angle the quicker the reaction to dry. (more of a skid /snap ball motion. The lower the ratio the smoother the break shape.

RATIOS DETERMINE THE BALLS BREAK SHAPE

The maximum and minimum ratios (break shapes) which should be utilized with your personal sweet sums is termed your ratio range. You need to determine your personal ratio range to utilize in conjunction with your total sums to accurately calculate your sweet sums. Mo frequently uses the lower ratio range for control drillings for easy conditions or wet/dry. He frequently uses the higher ratio range for more challenging conditions.

TOTAL SUMS

The total sums of your sweet spot will include a (+or- degrees). Adding sums to your sweet spot will add length to ball motion (increase total length to reach the roll phase...Subtracting sums from your sweet spot will decrease length of ball motion.)

example:

sweet spot of 100* (+or-20*) For dry or short oil patterns to increase length use 120* sums.(large ratio for long and strong layout or small ratio for long and smooth control layout)

For oily or longer patterns to decrease length use 80* sums. Utilizing ratios to achieve the desired break shape (high ratio=defined /sharp motion...low ratio=mid-lane roll)

You would adjust for specific balls,condition specific reactions,extreme conditions, etc. You would also adjust the numbers according to the amount of dominance (medium high rotation v.s. extremely high rotation) etc.

PLEASE NOTE: On ratios less than 1:1, Mo sometimes expresses ratios with the val angle reduced to :1

EXAMPLE: RANGE of 1.75:1 to 1:1.25 would be expressed as 1.75:1 to .8:1 (.8:1=1:1.25, etc.)

With low tilt, the rotation seems to effect the ratios a lot more than with medium tilts. A high rotation will decrease them a lot (what Mo calls PDW territory) and a low rotation will significantly raise them. There is more of an extreme adjustment comparitively. The ratios increase as the tilt decreases until you reach below 7*-10*. below that the ratios decrease. Part of the reason is because the maximum drilling angle is 90* and with low tilt, you need ratios which will take the ball down the lane. Here is a sample of how to adjust the chart for low tilt:

Low tilt chart