bran kulez wrote:I'm assuming you mean that A & B should be measured from the top of the groove. Is this correct?
BK, if you extend the two groove walls they intersect at a point. The horizontal plane containing that point should be the datum for dimensions A and B.
Hey, now you can add a sphere of various radii to scale and see where the contact locations and check clearance between the base of the sphere and the groove bottom !
One additional point, the NAB spec defines absolute minimum limit groove dimensions rather than what might be common practice. Yosh's excellent site might have some further info for real grooves.