Hi Chaz - that was the 2.2KW water-cooled variant.

As Jazz says if the bed was moving and allowing the cutter to take more than the desired 3.2mm then that might account for the spindle cut out. I've generally found that 8mm tools tend to survive very rough treatment, whilst 6mm and below don't. Last time I used an 8mm when something went wrong it welded itself into the plate and the machine then started walking itself off the table under spindle power, which was pretty scary, but the tool stayed intact.

I was even more grateful this time that the part wasn't ruined as I'd just finished cutting on the underside (hence the 4 hold down screws). This was the "cut out" toolpath in essence.