All pictures are "thumbnails".
full sized version.
right shows what
we had to start
with.  The rest of
the pictures show
the process of
The original floor boards were 1-1/2 inches
thick.  Fortunately, except for one hole all the
way through, the deteriorated part was only
in the upper 3/4".  The small router jig let us
get the nails out so that we could mill off the
top 3/4" without damaging the large router.  
Replacements were full length Heart Pine.