I have succeeded in making a helical spring following the various tutorials I've found.
But, since I want to represent a spring that has a flat end (i.e. it has the last coil perpendicular to the center line and ground flat I've tried a few different approaches and failed.
In part workbench, I tried to add a partial circle to the end of the helix. I got it to sweep. I then added an extruded plane and boolean it from the sweep. It did it, but the flat was not a solid (it showed up as a half pipe, thatif closed would have been the desired flat).
I tried something similar, adding the helix in part wb, then adding the circle to sweep in part design wb, then a another sketch with a simple pad. Then an exploded slice. This actually did cut correctly a produced a flat. But the resulting exploded slice has 2 slices. Not sure if that's the really good geometry or how to use the slice I want correctly for later operations.
In any case, what I'd really like to know is the correct or best way to model this.
OS: Ubuntu 19.04 (XFCE/ubuntustudio)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Build type: Release
Python version: 3.7.3
Qt version: 5.12.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/United States (en_US)