Mount the 3D Edge finder on the spindle and move from the starting point A to the point of contact B; Upon physical contact with the piece, a red light turns on and an acoustic signal activates, indicating that the position of point B is far from the center of the probe 3 mm ± 0.005.

Position the 3D Edge finder approximately in the center of the circumference, bring it into contact with a point of circumference C; 

Read the position and then move the device in the opposite direction; 

Then read the distance between point C and point D where the LED (red light) has turned on and the acoustic signal has activated;

 Half of the measured distance L is the center of the X axis; 

By repeating the same operation on the other Y axis, the center O of the circumference is obtained.