PJ wrote
My porcelain sink just laughed at my new Bosch SDS bit. I ended up
using (drill) mounted grinding stones to go through it.

Still took about 1/2 hour though (with stops to let bit & sink cool
down) to get through :-(

Eh?! Porcelain sink... SDS drill?! What are you trying to do, Shatter the
sink?!

I refrained from using hammer. But by the end was tempted to use
roto-stop and a big chisel :-)

Cheers

Paul.