I see an number of posts stating the R7.0 is to be used to create the high point for datum C this is incorrect as the R7 cannot produce the high point..
Datum C is the tangent of the radius 19.8 that is struck from the centre diameter.
I would measure the radius 19.8 then intersect it with a generic line to create the point C Datum
I see an number of posts stating the R7.0 is to be used to create the high point for datum C this is incorrect as the R7 cannot produce the high point..
Datum C is the tangent of the radius 19.8 that is struck from the centre diameter.
I would measure the radius 19.8 then intersect it with a generic line to create the point C Datum
Except that you won't be able to get a reliable radius measurement on such a small portion of surface. The method I described earlier is the closest way of simulating how an actual gauge would contact. You need to align to your datum A and B features, add in the theoretical 12.5° rotation back to centre line and then sample the surface where datum C is supposed to contact. You can gather points on that surface any way you see fit - vector points, scans etc. The density of those points will dictate how likely you are to pick up the true contact point of datum C.
I believe the easiest and quickest option would be to set the alignment as already mentioned then take a single point hit for the 19.8 DIM, the centre of the radius would have to be extremely far off to have any noticeable effect on the dimension.
