Spiral bevel gears in OpenSCAD I'm trying to design a "Lifting Table" in OpenSCAD which will consist of 2 concentric cylinders. On the inner cylinder I plan to mount 3 un-powered bevel gears vertically plus a 4th powered  one each at the proper location/angle to interface with external cylinder's spiral bevel gear and keep the external cylinder level. 

OpenSCAD's involute_gears library makes a bevel gear pair that is close to what I need, but the bigger gear is flat instead of a spiral.  How can I get the bigger gear to be a spiral and more than one rotation (level) 720 degrees for example?
I read this question a few months ago, and thought I knew what you wanted.  Re-reading it now confuses me a little.
But, I think you may be asking for a large, flat surface with a spiral in it, like the tightening mechanism in a 3-jaw chuck.  In effect, are you using the large cylinder as a worm gear to drive four gears which ride on it?
I thought you wanted more general bevel gears, and today I found a package in OpenSCAD that looks quite good.  it is found at: https://github.com/dpellegr/PolyGear
If this is the answer you were looking for, great.  If not, please comment here and I will delete this answer.