Ever since my friend Mike B. showed me a herringbone gear that he had printed from rhys-jones' Herringbone Geared Extruder blueprints, I've been interested in making my own. What would be really useful, I thought, would be a parametric version of this type of gear--then we could build custom gear sizes for robot parts, or whatever project we have going. So here is my attempt at using OpenSCAD to generate parametric herringbone gears.It's a work in progress, but I hope this might be useful in its current state and maybe as a community we can figure out the best way to generate these.Tweak the parameters (number of teeth, size of the base of a tooth, degrees of twist, number of segments, etc.) and then print in your handy dandy 3D printer, because it costs just as much to print a herringbone gear as it does a spur gear! (No other manufacturing process can make that claim that I'm aware of.)