See the pic. Weird results with a sweep on a 50 turn over 10" helix (0.200 pitch). A circle about 0.150 or smaller will not sweep the helix, but a circle bigger than about 0.150 will.

I had a look at http://moi3d.com/forum/messages.php?webtag=MOI&msg=1263.2 and others, but this isnt a 6 turner.

-Nick

edit: forgot to attach files.