module rail() {
  import("rail-bold.stl");
}

rail_width = 20;

base_thickness = 4;
base_width = rail_width / 2;

module profile() {
  difference() {
    x = sqrt(pow(rail_width, 2) * 2) / 2;
    difference() {
      translate([0, rail_width / 2, rail_width / -2]) rotate([45, 0, 0]) cube([base_width, x, x]);
      translate([0, 0, -rail_width - (rail_width / 3)]) cube([rail_width, rail_width, rail_width]);
      translate([0, 0, base_thickness]) cube([base_width, rail_width, rail_width]);
    }
    translate([0, 0, -1.5]) rotate([0, 90, 0]) rail();
    translate([0, 0, -2]) cube([rail_width, 2, 2]);
    translate([0, rail_width - 2, -2]) cube([rail_width, 2, 2]);
  }
}

axel_diameter = 8;
axel_tolerance = 1;
axel_center_height = 42 / 2;

module attachment(w = base_width) {
  difference() {
    hull() {
      cube([w, rail_width * 2, base_thickness]);
      translate([0, rail_width, axel_center_height]) rotate([0, 90, 0])
        linear_extrude(base_width) circle(d = axel_diameter * 2, $fn = 200);
    }

    translate([0, rail_width, axel_center_height]) rotate([0, 90, 0]) linear_extrude(base_width) circle(d = axel_diameter + axel_tolerance, $fn = 200);
  }
  profile();
  translate([0, rail_width, 0]) profile();
}

attachment();