I'm making a metal coil as per the picture below by extruding a plane along a spiral curve. I've added Fill Caps to make it solid
I need the coil to look smooth but the top and bottom to be sharp so I have added an edge split modifier and Subsurf modifier.
This works except for the ends of the coil which Blender tries to smooth as well instead of treating them as 90 degree angles.
Is there any way round this without turning the curve into a mesh?