OpenSCAD source code: Knob for NRC rotary positioner

Rotary Positioner - drive gear.scad

// Rotary positioner drive gear with knob
// Ed Nisley - KE4ZNU

include <BOSL2/std.scad>
include <BOSL2/gears.scad>

NumSides = 4*3*4;
$fn=NumSides;

Protrusion = 0.1;           // make holes end cleanly
HoleWindage = 0.2;          // make holes large enough to fit

ShaftOD = 5.5;

Knurling = "trunc_ribs";


difference() {

  cyl(h=9.5,d=16.0,anchor=BOTTOM,texture=Knurling,tex_size=[3.0,4.0]) position(TOP)
    cyl(h=1.8,d=15.2,circum=false,anchor=BOTTOM) position(TOP)
      color("Green")
        scale([1.03,1.03,1])    // nominal to physical hackery
          spur_gear(diam_pitch=60.0,teeth=24,pressure_angle=45,thickness=4.7,anchor=BOTTOM);

  down(Protrusion) {
    cyl(h=1.6,d=8.2 + HoleWindage,circum=true,anchor=BOTTOM);
    cyl(h=25,d=ShaftOD + HoleWindage,circum=true,anchor=BOTTOM);
  }

}

color("Red")
  right((8.2 + 16.0)/4)
    cyl(h=0.6,d=2.0,circum=false,anchor=BOTTOM);

More details on my blog at https://softsolder.com/2026/07/13/manual-drive-gear-for-nrc-rotary-positioner/