h=9.5;
r0=3;
$fn=50;
l=60;
w=30;
magnet_play=0.5;
magnet_l=19.5+magnet_play;
magnet_w=5.8+magnet_play/5.0;
magnet_h=2.7+magnet_play;
magnet_hole_h=0.86*h;
screw_play=0.3;
// Let's give one millimeter more
screw_head_r=7.8/2 + 5*screw_play;
screw_thread_r=4.1/2 + screw_play;
screw_head_h=3 + 8*screw_play;
color("white", 1.0) {
  difference()
  {
    union()
    {
      translate([0.15*l, 0.001, -0.19*h])
      rotate([90, 0, 0])
      linear_extrude(height = h/10)
      text("stiefel.tech", font = "Liberation Sans", size=6.5);
      translate([r0, r0, 0])
      hull() {
        for (x=[0:1:1]) {
          for (y=[0:1:1]) {
          translate([(l-2*r0)*x, (w-2*r0)*y, 0])
            cylinder(h, r=r0, center=true);
          }
        }
      }
    }
    union() {
      translate([0.1*l, w/2, 0])
      cylinder(h+0.001, r=screw_thread_r, center=true);
      // For screw head
      translate([0.1*l, w/2, h/2-screw_head_h/2+0.001])
      cylinder(screw_head_h, r1=screw_thread_r, r2=screw_head_r, center=true);
      translate([0.9*l, w/2, 0])
      cylinder(h+0.001, r=screw_thread_r, center=true);
      // For screw head
      translate([0.9*l, w/2, h/2-screw_head_h/2+0.001])
      cylinder(screw_head_h, r1=screw_thread_r, r2=screw_head_r, center=true);
    }
    translate([l/2, 0, 0])
    union() {
      for (x=[-2:1:2]) {
        translate([x*1.0*magnet_w-x*0.001, w/2, -h/2+magnet_hole_h/2-0.001])
        rotate([0, 0, 90])
        cube([magnet_l, magnet_w, magnet_hole_h], center=true);
      }
    }
  }
}