Other info on nailheading 

Received a note on nailheading to the effect: What if a direct-plate process
was used and the undercutting that is required to remove the unwanted coating
also etched away the thin layer of copper at the extension of the nailhead.
 Does this result in a circumferential void?. I believe it would; however, it
probably does not have have any relation to the often specified 150% of the
base foil thickness, and may also happen with a 125% nailhead.      

Other incidental on nailheading:  It is remembered that Bob Lomerson-ex Gen
Dynam-Ft. Worth  has a patent on a nail heading process wherein he imposed on
the top of the drill stack during drilling a layer of another foil and
nailheaded (smeared) it all the way through the the hole thus eliminating
electroless processing.

Phil Hinton
hintpwb1.aol.com