Creating A Physical External Thread

[rc0213]

We have Creo 3.0. And, I have been trying to create a physical external thread, but, keep running into a problem.

I click on the Helical Sweep icon.
I click on the Reference tab.
I click on Edit icon next to Internal Profile Section.
I draw the line on the edge of the cylinder.
I add a centerline in the middle of the cylinder.
I add a triangle geometry on the coincident to the line on the edge of the cylinder.

This is where I keep getting stuck.

I adjust the pitch, and, the check icon is greyed out. I don't know what to do from this point.

What do I do?

 

[3DDave]

I never used the helical sweep icon - however using an equation to create a helix as a reference still ended a similar way if the resulting cut would leave a zero width edge where the cylinder surface was. Making the cut so it allows a small flat to remained worked.

I expect that creating a cylinder at the pitch diameter and cutting material below the pitch diameter and then creating a protrusion to add a sharp triangle profile above the pitch diameter would also work.