b = 84;
h = 180;
d = 84;
w = 5;

difference () {
    difference () {
      
        translate ([0,0,h/2])
            cube ([b,d,h], center = true);

        translate ([0,-d/2,h])
            rotate ([30,0,0])
            cube ([b+1,d,h/2], center = true);

        translate ([0,d/2,h])
            rotate ([-30,0,0])
            cube ([b+1,d,h/2], center = true);
    }

    difference () {
     translate ([-5,0,h/2])
            cube ([b+2,d-w,h-w], center = true);

        translate ([0,-d/2,h-w/2])
            rotate ([30,0,0])
            cube ([b+1,d,h/2], center = true);

        translate ([0,d/2,h-w/2])
            rotate ([-30,0,0])
            cube ([b+1,d,h/2], center = true);
    }
  translate([b/2,0,15])
rotate([0,90,0])
cube([12, 30, 10], center=true);
       
// schroefgat:
translate([-b/2 + 20, b/2-70
    , h/2 - 1])
  rotate([0,90,0])
    cylinder(h=b+50, d=4);
    
    translate([-b/2 + 20, b/2-20
    , h/2 - 1])
  rotate([0,90,0])
    cylinder(h=b+50, d=4);
    
}