I manage to make a helix curve and cut extruded solid with lofted cut, but i dont know how to remove rest of solid material because helix line is cone with variable pitch and diameter, anyone have a beter solution how to make this model or how to remove rest of material which can be seen on pictures 3 and 4. On this pictures can be seen that my lofted cut is in the extruded solid. I don't have specified any dimension except starting diameter 60mm and length about 150mm. I'm new to 3D modeling and learning. Thanks for all answers!