Well explained, TomG. Spot on.
When using a straight tooth milling cutter in that vertical mill fashion (the R8 arbor shown in post #10), there's a lot of "holder" below the cutter so you can't get very close to the table or vise. There's a "Peterson Tool" flush milling arbor avalable, but they are hard to find and very spendy. I've only seen them in NMTB40 and NMTB50 tapers.
When using a straight tooth milling cutter in that vertical mill fashion (the R8 arbor shown in post #10), there's a lot of "holder" below the cutter so you can't get very close to the table or vise. There's a "Peterson Tool" flush milling arbor avalable, but they are hard to find and very spendy. I've only seen them in NMTB40 and NMTB50 tapers.