I used a reinforced cut off wheel on max speed (35,000 RPM)
All it needed was a slight bit of pressure, and it sliced through with no problems.
From what i hear a lot of guys use the diamond edged wheel,
but its circumference is smaller then the one i used. I whould have had to cut all the way around the branch and try to meet in the middle. With the blade i used i was able to cut all the way through from one side.