Geoff,

Since your dealing with sheet metal you are also most likely dealing with stamped holes or slots. I usually ask our engineers the purpose and intent of the hole or slot, and if it is thin sheet metal I ask if there is really a need for this to be verified as it almost impossible to measure and get a reliable answer. If they have to have it, I program my cylinder to make as many points per circle in the cylinder as possible and even then you are pushing things to the limit. I have asked for the purpose of the call out to be challenged on thin material with justification with regard to accuracy and time spent taking the measurements.

Duane Wade