Okay Fusion 360 doesn't like me. I'm going to have to spend some time learning this app before I can make any actual progress. I tried out some of the other options (FreeCad, 123D, DesignSpark Mechanical, etc) but none of them could open the Inventor IPT file format, and the STL file is already a mesh, so hard to stretch it and keep the lines straight. And anything else (that might import an IPT) appears to cost money, so I guess I need to keep trying to figure out Fusion 360. Boy I wish I could reassign these mouse buttons...