Big hole drilling on a cylindrical vessel

I'm not sure there is a way to drill a hole like that without some Ginormous investment in tooling. How big is the vessel? It sounds like maybe you should torch a bigger hole and weld a premade .3m "adapter" in. If you just need the hole, torch it or plasma cut it undersized, and finish by hand. Not sure what else to tell ya:(

ssancak wrote:

These holes are made now allmost the same way as you told.Vessel diameter is approx. 3m.