These are actually the carrier bearing supports welded to the crossmember in my bus, unknown steel alloy wasn't cooperating so I just ran the lathe as slow on the spindle and feedrate as it'd go resulting in almost zero toolpressure. Sharp tool is actually cutting and breaking a chip, the surface finish was amazing. Half way through I went up a notch or two on spindle speed. High speed tools do a great job and they are extremely economical if you treat them right and aren't out for super mad sick production profits.