We use these in elevated water tanks for municipalities for their drinking water supply.

The cone is a smooth or flared transition between the stem of the tank and the sphere. The tank is similar to a golf ball on a tee. It is known as a water sphere type tank. The flared cone goes between the shaft or stem of the tank and the sphere on top.

I have attached a drawing of the development of the double curved cone. The thickness runs between .5 and 1.5 inches. The drawing has the dimensions.

We have been rolling the exterior radius (usually around 50 degrees) and using a rectangular male/female die with the parallel portion of the die forming the inside
radius of the cone and the longitudinal curve being formed at 50 degrees.

The parallel radius is equal to the lower or tightest radius of the cone. We loosen the
amount of pressing as we move from the tighter (smaller end) to the top (bigger end).

While this has proven successful, it is time consuming and does not make each piece 100% identical. This requires additional fit up time to make the finished product within tolerance. We would like to make a die that would press the entire piece in one press. Our largest press is 750 Ton.

I would appreciate any ideas you may have.

Thank you in advance for your time and thoughts.