I am attempting to create a true model of a tri-lobe helix thread of an M3 thread forming screw.

The screw has an effective nominal diameter of 3mm (C), and the three lobed cam that measures 2.9mm (D) nominally across opposite lobes.

I am able to sweep along a standard, (constant radius), helix curve just fine, but cannot think of a relatively simple way to create a lobed helix path that I can sweep along.

Short of creating a series of unwieldy sketch geometries, I am wondering if anyone has a trick or two up their sleeve that could help me with this problem.

Below is a screen-grab of the catalog spec I am attempting to model.