Hi Anders!
We are using an application that searches for the center of bolts. Using the handEye calibration we can touch the center of the bolts. For this, we create a special gripper as you can see in the picture:
With this, we could roughly measure the total error. I understand, that the error includes the handEye calibration error, the center of the bolt detection error, the UR error, the error of the camera and so on. But in total, we were very close to ~1mm