Angle Between Features

[[Da...]]

Good morning, I am having a problem measuring this attached part. I'm trying to report out the angle between the C'bored holes and the related T/P requirements. The holes are at the 3 and 9 o' clock location (180 degrees apart). When the part is run on our O-Inspect 322 model machine, it's reporting out a 177.9 degree angle result, and reporting .005/.006 T/P values for the Datum D/ and the right side thru holes (.49975 basic diameter). We have inspected the part manually and the angle and position are reading well within the B/P requirements. I have the base alignment set up as Datum B for Spatial Rotation, right side counterbore depth for Planar Rotation, an upper circle around Datum A for the X & Y Origin, and Datum B for the Z origin. Not sure if this alignment is stable enough, and if the length of the flat designated as Datum C (approx .288" long) is helping with this problem, The part is just clamped in a vise on the flats. I ensured that the flats were fully flush with the vise and the part was level. I'm still very new to the CMM world so any help would be appreciated. Thanks.

angle bp.pdf

[[Ri...]]

A needs to be a cylinder or some other type of axis line. It will control your spatial rotation, as well as the X,Y origin.

I would start with a Cylinder for Datum A, a Plane for Datum B, and a Plane for Datum C. With enough enough data, that will be plenty stable.

[[SH...]]

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Calypso calculate the bore pattern true position with best fit alignment obviously angle calculate based on that alignment.You have to change your BA according to the order of datum in the FCF.