Quote Originally Posted by blueheckle View Post
No I mean across the top of the neck one size could be a few thou higher than the other thanks
If Graham is correct & the sides of the case are not parallel then you cannot use a square to check the neck face for true, because the face of the neck will not be at 90* to the case side

If you put the square on the other side of the case the low point would appear to swap sides.