motorbuldgedia=9.5;  // mm , buldge on motor can
motorbuldgeheight=2; // mm , height of buldge on motor can
motorshaftdia=3.2; // mm , small protuding motor shaft
motorshaftlen=0.5; // mm , length of motor shaft protrusion
motoroutdia=18; // mm , widest point of hub, will include M2 screw holes
motorfixdia=12; // mm , diameter of screw mounts
motorscrdia=2;  // mm , diameter of screw holes
motorscrheaddia=3.8;  // mm, diameter of screw head
motorscrheadlen=17;   // mm, length of screw head, which is also entry hole
motorhubheight=12; // mm, hub height

coneheight=2;  // mm, cone height

shaftdia=5;  // mm , of drive shaft
shaftholderdia=17; // mm , of plastic cylinder than grips shaft
shaftholderheight=12;  // mm , length of "

shaftslitwidth=0.5;  // mm, width of slit that shaft screws will (attempt) to pull shut

shaftflatlen=7;  // mm length of flat section filed onto shaft

gripboltdia=3;  // mm, diameter of gripping bolt (two of)
gripboltlen=9;  // mm, length of gripboltdia section, ie, just slightly wider than the drive shaft.
gripboltheight=22;

$fn=100;

difference()  // motor hub
 {
     union()
       {
          cylinder(motorhubheight,motoroutdia/2,motoroutdia/2);  // main hub that mounts to motor
           
          translate([0,0,motorhubheight])
   cylinder(coneheight,motoroutdia/2,shaftholderdia/2);   // cone that joins hub with shaft gripper
           
           translate([0,0,motorhubheight+coneheight])  // shaft gripper
              cylinder(shaftholderheight,shaftholderdia/2,shaftholderdia/2);   // shaft grip
           
           translate([0,0,0])
              translate([-shaftholderdia/2,-shaftholderdia/2,0])
              cube([shaftholderdia,shaftholderdia,gripboltheight+gripboltdia*2/2]);
       }
   union()
    {
      cylinder(motorbuldgeheight,motorbuldgedia/2,motorbuldgedia/2);  // bulge in motor can
      translate([0,0,motorbuldgeheight])cylinder(motorshaftlen,motorshaftdia/2,motorshaftdia/2); // motor shaft protrussion above bulge in can

       difference()
         {
             cylinder(shaftflatlen+1,shaftdia/2,shaftdia/2);
             translate([-shaftholderdia/2,-shaftdia-1.1,0])  // to outer edge, in 1mm
                  cube([shaftholderdia,shaftdia,shaftflatlen+1]);      
             translate([-shaftholderdia/2,shaftdia/2-1,0])  // to outer edge, in 1mm
                  cube([shaftholderdia,shaftdia,shaftflatlen+1]);
         }

      for(i=[45:90:360])
         rotate([0,0,i])
            translate([motorfixdia/2,0,-1])
               union()
                 {
                    cylinder(motorhubheight+2,motorscrdia/2,motorscrdia/2);   // screw holes in hub, +1,+2 to ensure the holes break through the surface
                     translate([0,0,motorhubheight])
                       {
                          cylinder(motorscrheadlen,motorscrheaddia/2,motorscrheaddia/2);
                           translate([0,0,motorscrheadlen])
                              cylinder(motorscrheaddia,motorscrheaddia/2,0);
                       }
                 }
                 
       translate([0,0,motorbuldgeheight+shaftflatlen-1])  // shaft gripper 
             cylinder(shaftholderheight+10,shaftdia/2,shaftdia/2);   // hole for shaft
         //screwhole();
                 
    translate([0,0,motorhubheight+1])  // shaft gripper 
           translate([-shaftslitwidth/2,-(shaftholderdia+2)/2,0])
                cube([shaftslitwidth,shaftholderdia+2,shaftholderheight+2]);   // slit
        
          for(i=[90:180:360])
            rotate([0,0,i])
           translate([shaftdia/2+gripboltdia/2,0,gripboltheight])
          rotate([90,0,0])
          translate([0,0,-gripboltlen])
         cylinder(gripboltlen*2,gripboltdia/2,gripboltdia/2);
    }    
                 
 }