To Create a Parametric Helical Solid with Known Dimensions

Create a profile (closed cell, closed line string, shape, complex shape, circle, ellipse, or closed B-spline.)
Select the Helix Feature tool.
Turn on settings for Height, Top Radius, Bottom Radius, and Pitch, and input the required values.
Select the profile (or select the cell).
Enter a data point to define the direction of the bottom radius.
Enter a data point to define the direction of the height.
The height displays dynamically.
Accept the Top Radius.
The helical solid dynamically displays.
Accept to complete the construction.

Creating a helical solid, with all parameters set. | Left: Select the profile (1), define the direction of the bottom radius (2) and the height (3), then accept the top radius (4). | Accept (5) to complete the construction with Pitch set to Constant (center) and Varying (right).

Rendered image of the completed helical solid with pitch set to Constant (left) and Varying (right).