In this video I install a mechanical boss onto a cast iron soil pipe. How to cut the 57mm hole in the soil pipe can be seen here- https://www.youtube.com/watch?v=xm0GGDsw2OU
A mechanical boss can be used to connect a waste pipe, either 32mm or 40mm into a soil stack. Mechanical boss’s have the advantage that you can use them on cast iron or plastic soil pipes. There are a few different sizes available so please ensure you get the correct one.