$fn=50;

//#cube([30,30,26], center=true);
nut=30;
Ra=3;
Ri=1.4;
Rc = 1; // Radius am Center
Wi=19.5; // innere weite
Wl = 8.2; // lichte weite
heigth=25;

difference(){
hull(){
translate([-(nut/2-Ra), -(nut/2-Ra),0])  cylinder(r=Ra, h=heigth);
translate([-(nut/2-Ra), (nut/2-Ra),0])  cylinder(r=Ra, h=heigth);
translate([(nut/2-Ra), -(nut/2-Ra),0])  cylinder(r=Ra, h=heigth);
translate([(nut/2-Ra), (nut/2-Ra),0])  cylinder(r=Ra, h=heigth);
}

cylinder(d=6.8, h=25);

union(){
translate([-8.2/2, -15,0]) cube([8.2, 2.1, heigth]);
hull(){
translate([-Wi/2 + Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wi/2 - Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);


translate([-Wl/2 + Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wl/2 - Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
}
}
rotate([0,0,90])
union(){
translate([-8.2/2, -15,0]) cube([8.2, 2.1, heigth]);hull(){
translate([-Wi/2 + Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wi/2 - Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);


translate([-Wl/2 + Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wl/2 - Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
}
}


rotate([0,0,270])
union(){
translate([-8.2/2, -15,0]) cube([8.2, 2.1, heigth]);hull(){
translate([-Wi/2 + Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wi/2 - Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);


translate([-Wl/2 + Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wl/2 - Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
}
}

rotate([0,0,180])
union(){
translate([-8.2/2, -15,0]) cube([8.2, 2.1, heigth]);hull(){
translate([-Wi/2 + Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wi/2 - Ri, -(15-2-Ri) ,0]) cylinder(r=1.4, h=heigth);


translate([-Wl/2 + Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
translate([+Wl/2 - Rc, -(15-9.7+Rc) ,0]) cylinder(r=1.4, h=heigth);
}
}
}