Lots of chips, for sure.
The mortises were made with a drill press and 2" hole saw that was about 2" deep. Holes were drilled on 1" centers and slugs knocked out with a chisel. I made four extensions from 3/4" round bar to drill past the center, then rotated the post to drill from the other side. Pilot holes, 1/4", were pre-drilled. The corners were squared up with a Husky electric chain saw.