OpenSCAD source code: Flashlight mount ball

Fairing Flashlight Mount.scad: Flashlight ball excerpt

//- Ball around flashlight
// Must print two!

module BodyBall() {

  difference() {
    intersection() {
      sphere(d=BallOD,$fn=2*NumSides);                      // basic ball
      cube([BallLength,2*BallOD,2*BallOD],center=true);     // max of flashlight grip length
    }
    translate([-LightBodies[FlashIndex][F_GRIPOD],0,0])
      rotate([0,90,0]) rotate(180/NumSides)
        PolyCyl(LightBodies[FlashIndex][F_GRIPOD],2*BallOD,NumSides);        // flashlight body
    for (j=[-1,1])
      translate([0,j*BallScrewOC/2,0])                // commmon screw offset
        translate([0,0,-BallOD])
          PolyCyl(BallInsert[ID],2*BallOD,6);         // punch screw shaft through everything
    translate([0,BallScrewOC/2,-Protrusion])
      PolyCyl(BallInsert[OD],(BallInsert[LENGTH] + 3*ThreadThick + Protrusion),6);  // threaded insert
    translate([0,-BallScrewOC/2,BallThick])
      PolyCyl(BallScrew[OD],BallOD,6);                // screw head clearance

    translate([0,0,-BallOD/2])                        // remove bottom half
      cube(BallOD,center=true);
    translate([0,0,BallOD - BallThick/2])             // slice off top = bottom for E-Z build
      cube(BallOD,center=true);
  }

  if (Support) {
    NumRibs = 24;
    RibHeight = (BallOD - LightBodies[FlashIndex][F_GRIPOD]/cos(180/NumSides) - BallThick) / 2;
    ChordC = 2*sqrt(BallThick*BallOD/2 - pow(BallThick/2,2));
    intersection() {
      cube([BallLength,2*BallOD,2*BallOD],center=true);     // max of flashlight grip length
      translate([0,0,BallOD/2 - BallThick/2])
        for (i=[0:NumRibs - 1])
          rotate(i*360/NumRibs + 180/NumRibs)           // avoid screw holes
            translate([ChordC/2 + BallOD/8,0,-RibHeight/2])
              cube([BallOD/4,2*ThreadWidth,RibHeight],center=true);
    }
  }
}

More details on my blog at http://wp.me/poZKh-6V3