I have a part with 2 parallel vertical pieces. The print calls out 3x Ø11±0.5 THRU. How would you gentlefolk approach this? Construct a cylinder for each set and report the True Position? Report the true positions of each set of 2 circles? Construct a cylinder and define it as a datum and then report concentricity of the end circles to that datum cylinder? Or would it be better to move the origin to one of the circles and report the coaxiality of the other circle to the "origin"? If the lattermost option, what tolerance would you put on that coaxiality?
Also, while I have your attention--I've never seen "runout" on the edge of a flat part. Does this mean they are going to accept UP TO 15° from perpendicular on that edge?
What I decided to do was to construct a MAX_INSCR cylinder from the two circles and define that cylinder as a datum, then dimension the two circles using concentricity to that datum cylinder. It's giving me values of 0.002 and 0.025, so unless one of you gurus tells me otherwise I'll go with that.
Now, whether or not the customer will freak out when they see the concentricity on the dimensional report is another issue (because technically it's not "called out" on the print as a feature control frame).
What I decided to do was to construct a MAX_INSCR cylinder from the two circles and define that cylinder as a datum, then dimension the two circles using concentricity to that datum cylinder. It's giving me values of 0.002 and 0.025, so unless one of you gurus tells me otherwise I'll go with that.
Now, whether or not the customer will freak out when they see the concentricity on the dimensional report is another issue (because technically it's not "called out" on the print as a feature control frame).
