Drilling into copper HW tank.

[Stevex]

I'll be fitting a couple of Essex fl@anges to my HW tank soon. required hole is 38mm.
I know these tanks are quite thin and can rip easily so what's the best way to drill them with a hole cutter?

 

[gmartine]

Comparatively expensive but a screw hole punch.

 

[Knappers]

Comparatively expensive but a screw hole punch.

How does that work inside a tank?
I'd use a holesaw - fast and gentle.

 

[gmartine]

Fair enough, you'd need to feed through the immersion apperture as you would the flange.

 

[Last Plumber]

I have always used a holesaw for that kind of thing. Make sure it is sharp, don't press too hard. Get rid of burrs.