I have modeled a thread form which will be made in plastic and therefore would like to cap each open end of the thead.At present I have used a swept blend to create the cap , if I try toapply tangency, the bottom of the cap lifts from the thread surface so insteadI have added rounds to smooth it out. This works okay but the trajectory of the cap does not follow the helical trajectory of the thread..........any better ways of capping threads out there?