it is a very simple geometry calculation, first thing you need to know you 'angle' of oval, it is the horizontal line vs the direction of the widest part of your thumb, then, use some measuring tools to check the height and width of your thumb, check the different, use the height as the first Pilot hole this is the first hole with the actual span length with.
then this is the latest tricks:
minus the width and the height, it is the baseline, use this to plot the sin and cos with the 'angle' of oval. cos is the way to get the horizontal move, sin is the way to get the vertical move
you then will get the actual total vertical and horizontal move that you need with the drilled pilot hole, divided it into two part, then. reset the digital meter of your drill mill to zero, . use at least 2 moves. up + left, then down + right (right hand, left hand reverse) with the above calculation result.
I used this method even in all 3 finger holes for lots of customer and all feel very happy with that accuracy, however, because of some thumb shape issue, sometime need to use garbage ball to test drill first
Edited by lane1lover on 11/9/2011 at 0:34 AM
