Using a ball end mill on a lathe to round an inside bottom

[DaveD44]

Update: I successfully made the part and quartered it. After first finishing the ID down to the start of the 1/4" inside radius, I mounted the 1/2"...

[DaveD44]

I bought a Volstro, 30 years old, almost unused. I suppose this is what you are asking about? It is a wonderful tool, one of the highest quality pieces...

[DaveD44]

Good input! For clarity, I am attaching a portion of my 3D drawing of the tank bottom perimeter. I will mount the ball end mill in a boring bar holder...

[DaveD44]

I will be fabricating some small straight angle irons, radiused on the inside and outside corners, and some quarter rounds with the same profile, to be...