Oh and it gets better! 
I tried to make a hexnut by the same token. YOU CAN'T! ... not with helical sweep.
I tried to make a standard hexnut 1/4-28 (UNF) and it wouldn't cut the triangle thread no matter what I tried.
Go ahead, I challenge you: Sharp ID and OD based on 1/28" pitch, 7/16" hex and 7/32 thick.
I ended up having to use the VSS to make the cut. LAME!
If you can accomlish this with the Helical Sweep, please post the file.
Remember; sharp edges using a 60/60/60 triangle shape and NO FUDGING!