pipe_bearing.scad

pipe = 1/2;

bearing_id = 3/8;
bearing_od = 7/8;
bearing_w = 9/32;

// max overlap is 0.50 == 50%
pipe_overlap_multiplier = 0.35;
pulley_od = 3;
pulley_lip = 1/16;

pipe_segment = sqrt(
  (pipe*pipe_overlap_multiplier)*
  (pipe*(1-pipe_overlap_multiplier))
  ) * 2;
pulley_width = pipe_segment + (2 * pulley_lip);

rotate_extrude($fn=200){
  difference(){
    polygon( points=[
      [bearing_od/2,0],
      [bearing_od/2,bearing_w],
      [bearing_id/2,bearing_w],
      [bearing_id/2,bearing_w+(pulley_width-(2*bearing_w))],
      [bearing_od/2,bearing_w+(pulley_width-(2*bearing_w))],
      [bearing_od/2,pulley_width],
      [pulley_od/2,pulley_width],
      [pulley_od/2,0],
      [bearing_od/2,0]
    ]);
    translate([
      ((pulley_od/2)+(pipe/2)-(pipe*pipe_overlap_multiplier)),
      pulley_width/2,
      0
      ]){
      circle(pipe/2, $fn=150);
    }
  }
}