Hi

In order to plumb-in a washing machine, I need to connect to the old cast
iron soil pipe to carry away the waste. (The pipe is just over 4 1/4"
diameter.)

Can anyone recommend a good way to cut the hole in the pipe, to connect a
boss ?

I've seen an old post where someone recommended drilling a ring of closely
spaced holes and then joining the holes so the disc can be removed. But I
don't see how you'd be able to drill the holes closest to the wall.

Whatever the method, I don't want to risk cracking the pipe - presumably old
cast iron is fairly brittle.

Many thanks

Steve