I am presently working on some large 12" 45 degree cones with 2 hole patterns around the center. My insert drill won't let just plunge or peck through it. I have been spot face them with a 1" end mill down far enough to make 1" flat. Then I call up the 1" insert drill and poke rite thru.
The angle of the cones eats up 1" end mills really bad on the corners.
I have to go over 3.5 deep to break through.
Any suggestions or comments .