JimK wrote in
:

/you may de able to counterbore from the top by constructing some sort
of too that you push up from underneath and then attach to the drill
/q

Mmm like a Thunderbirds style reverse cutting drill bit thing ? Gorra
link!?

Jim K


Think about the state of it in years to come when damp has had its effects.
A counterbore will be very vulnerable to damp.