Positional tolerance with group deviation allowable

[fortjp500]

I have two plates that are the same with the same hole pattern on front and back plate. Normally the position tolerance at MMC would be 0.06" for assembly to work perfectly. However the part could be allowed to rotate 0.5 degree after welded at assembly by the technician. In essence once the front bolts are in "loosely" there would be some rotational degree of freedom that we are limiting to 0.5 degrees of the finished part. By rotating the finished part slightly, the backside hole pattern would shift as a unit up or down to get the part to align and allow the back bolts to go in. Is there a proper callout for this that would allow the backside holes to shift together as long as the distance between them is not too large say ± 0.060"? Two front holes are typically the secondard and tertiary datum, the first being front plate's plane. In short, the plates can be drilled accurately but the welding process is what makes the plates sometimes shifted up or down from each other and some of that plate misalignment is allowable but the above was my best attempt at explaining where we draw the line for what is considered a bad part, one where the holes on the backside plate are not within perhaps 0.06 of the average location? Where that average location is controlled based on 0.5 degree over the length of the part. Is that something positional tolerance can do?

 

[3DDave]

Perhaps a diagram? Ordinary positional tolerancing does this exact thing, but it's not clear what additional amount you want to allow. "Distance between them ... ± " is not going to be covered by a geometric tolerance.