Using a mandrel on a 4" drill head. I tried it on an old aluminum rim, it works well even at 12 inches long. It's solid for its length, has very little chatter, I'll buy another one as a backup.
Pros
Fits CCMT 32.51 or CCMT32.52 inserts. S16T SCLCR4. Profiling mandrel for semi-finishing and finishing