I have a 4inch copper coupler plan to solder stainless ferrule each end. I need a 53mm hole to create a 45 degree junction into it using a 50mm expanded copper elbow. Should I
A) use tct hole saw in drill press
B) buy a sheet metal punch.
The hole I need to cut takes place in both stainless ferrule and copper coupler.
I want to do it right once will cost me more to replace bits then buy right tool for the job. I once drilled 12mm hole in a end cap that took some doing..