chipboard screw modeling

I tried a couple of methods to model a feeder screw very similar to a chipboard screw. No success so far.

I think helical sweep along variable trajectory might be the solution.
The swept profile changes (trapezoid shape - bigger in the middle, smaller at both ends of the thread) along the trajectory. (actually runs to zero a the tip)
Thread external and core diameters are also changing.
Any suggestions are welcome.