dgeesaman
Gold $$ Contributor
It’s possible that Whidden paints the end with “no-carb” just for this situation.I have taken a bunch of dies down and on the bottom any carbide tool will make it seem not hardened. Its only hardened a few thou deep its not tool steel.
Another possible reason is the carburizing would overharden the bottom where there is a thin wal and it would become brittle.
David