Patent ID: 7210321

Claim:
A method of measuring centreline runout and out of roundness for a shaft, said shaft having a central longitudinal axis extending between the centres of opposing ends of said shaft, said method comprising the steps of: a) selecting a first measurement plane transverse to said central longitudinal axis; b) measuring the distance between said central longitudinal axis and each of a plurality of angularly spaced measurement points located on the outer surface of said shaft in said first measurement plane with a measuring means; c) calculating the position of the centroid of the transverse cross-section of said shaft defined in said first measurement plane based on the distances measured in step b); d) calculating the distance between said centroid and said central longitudinal axis, thereby providing a centreline runout measurement of said shaft in said first measurement plane; e) calculating the distance between each said measurement point and said centroid; and f) calculating an out of round measurement of said shaft in said first measurement plane is based on the distances measured in step e).