Another company heavily involved in rotary-flap peening has conducted trials with the magnetic holder and found the AMS/3M adjustment to be more accurate than the previous Boeing rule. As stated, the new Boeing rule will increase the gap.
We discuss the differences during our RFP training course. With the AMS/3M having a larger conversion ratio while beginning at 0.005" the two (old) standards would yield the same result when adjusting a measurement near 0.0125", and of course 0.0".
I have speculated that Boeing created their original rule as an easier method of conversion and selected their multiplier of 0.77 was to have their result equal 3M's targeted intensity value, 10A. Both the Boeing and 3M conversion yield almost identical results; Boeing's 0.013x0.77=0.0100, 3M's ((0.013-0.005)x0.6)+0.005)=0.0098.
Applying the Boeing's RevD method to the same measured arc height is a big change. ((0.013-.005)x0.77)+0.005)=0.0112. The difference between the two standards lessen as you near 0.005, but increase with larger arc height values.
I do hope this is a simple mistake. If it stands, all existing rotary flap curve solvers will need to be changed. There's also the question if the old Boeing conversion is meant to still be used on older parts/airframes. If so, the curve solver programs will have to offer both methods and hope the technician knows which one to use.
I'm still waiting for word back from the guys that have the answers.
