I am attempting to bore 65mm holes in 4" aluminum bar. A photo of the result is attached. It's ugly! I have experimented with alot of variables but still get this tearing of the metal instead of a clean cut.

Machine: Tormach PCNC 1100 series 3
Controller: PathPilot
Tool: 1/2" Glanze through-coolant boring bar (steel)
Insert: CCMT, tried one for steel and one for aluminum with the same result
Surface speed: 150-500 meters/min
Feed rate: 550-800 mm/min
depth of cut: 0.25-0.5mm
Insert is parallel to X-axis and centered in the bore

All the other cuts on the machine are working great. Facing, turning, parting are all no problem. What am I doing wrong with boring?