$fn=60;

include <BOSL2/std.scad>
include <boltsos_0.4.1/BOLTS.scad>

module screw() {
    cylinder(h=4.5, d=9, $fn=6);
    translate([0,0,-18]) cylinder(h=25,d=5);
    translate([-4,0,2.25]) cuboid([12,9,4.5]);
}
    

difference() {
    union() {
        ycyl(l=20, d=16.8, rounding=1);
        translate([0,10,0]) ycyl(l=1.5, d=20, rounding=.5);
        translate([0,1,0]) ycyl(l=21, d=8.5, rounding=.5);
    }
    rotate([0,90,-90]) screw();
}