Cutting Cast Iron and Plastic/Cast Connections ?
You cut the cast iron with a reciprocal saw like a Milwaukee Sawzall all. Use heavy metal blades like Lenox 614R type. I start with the six inchers. It will take several to get through the side of the pipe . Once you have made a cut into the pipe – it will go faster. You’ll need the long metal blades to finish the job. At first-it will seem like it will never cut it-but it will. Use Mission or Fernco No Flex couplings- one on each side-to connect the plastic and cast iron. Do not forget the vents!