Insert a shaft into one hole of the green object.
Ensure no gap between shaft and hole.
Get the highest value E1 of the shaft at the measuring position.
Turn the object 180 deg.
Get the highest value E2 of the shaft at the measuring position.
Non-parallelism P = (E1-E2)/(A-B/2)
A: distance from indicator centerline to the positioning face of the basic axle.
B: length of the lower hole of the object.