Hi All,

I'm trying to create a custom thread with both variable thickness and taper (i.e. the thickness of the profile of the thread grows as it rotates down the screw shaft, and at the same time the taper of the helix defining the thread trajectory tapers...see image below for illustration).  I think I need to use a lofted boss feature, with several sketches defining the profile as the thread revolves around the screw shaft, as well as several guide curves (4....on for each corner of the sketch?) to define the trajectory of the sketches.  The problem is I need to maintain some very specific angles/lengths for the individual sketch profiles, while ensuring the helical guide curves intersect with these sketches so my lofted boss will work.  However, the helical curves are created using values independent of the sketched profiles (i.e. revolution and pitch....which don't necessarily always lead to intersecting my sketched profiles).  I've considered doing a "curve through reference points" curve, but am not sure that will gaurantee me a true helix (need to maintain a specific pitch all the way down my threads).  Can anyone recommend a better way to do this?