Dual Angle Ratio Guide
Contents
'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.
BENCHMARK RATIO
This is necessary To accurately calculate the drilling angle and the val angle individually.
Find initial tilt ratio on Athery's tilt chart
Adjust this ratio higher or lower for rotation. ( move box to left or right on chart. note: extreme speed or rev dominance can accentuate this which requires more of an adjustment)
Calculate the ratio range. (this is necessary to calculate all layouts to personalize your desired ball motions.
INITIAL RATIO from TILT
. The middle column (Initial Ratio from TILT) gives approximate ratios 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
HIGH OR LOW ROTATION
high rotation and/or high rotation with extreme speed dominance=DECREASE RATIOS.
(adjust to boxes further right on the chart)
low rotation and/or low rotation with extreme rev dominance = INCREASE RATIOS.
(adjust to boxes further left on the chart)'
RATIOS
RATIOS DETERMINE THE BALLS BREAK SHAPE
The drill angle determines the length of the skid phase of the ball motion.
The val angle determines the length of the hook phase of the ball motion.
The drill angle + val angle = the total length before the ball reaches the roll phase of the ball 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.
TOTAL SUMS
Degrees of drilling angle + degrees of val angle = TOTAL SUMS
The total sums of your sweet spot will include a (+or- degrees). Adding these degrees to your total sums will add length to ball motion (increase total length to reach the roll phase...Subtracting these degrees from your total sums 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.(use alarge ratio for long and strong layout or use a 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)
RATIO RANGE
The maximum ratio and minimum ratio (drill angle/val angle) which should be utilized with your personal sweet sums is termed your RATIO RANGE.This is how far you can deviate your ratio both higher and lower from your benchmark ratio. It can be calculated by choosing boxes left and right of your chosen ratio on the chart above. 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.
You need to determine your personal ratio range to utilize in conjunction with your total sums to accurately calculate your preferred layouts or 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.
PLEASE NOTE: On ratios less than 1:1, Mo sometimes expresses ratios with the val angle reduced to :1
1:1.25 would be expressed as .8:1 (.8:1=1:1.25, etc.)
TILTS BELOW 10*
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:
CLICK ON "LOW TILT CHART" FOR PDF CHART.
