$fn = 20;
through = 20;
d = 4.5;
e = 0.01;

function midxy(a, b) = [(a[0]-b[0])/2, (a[1]-b[1])/2, 0];
function centerx(w) = [-w/2, 0, 0];

module rcube(s, r=2) {
	hull() {
		for (y = [r, s[1]-r]) {
			for (x = [r, s[0]-r]) {
				translate([x, y, 0]) {
					cylinder(r=r, s[2]);
				}
			}
		}
	}
}

module midmounts() {
	m = 2;
	ow = 18.5;
	oh = 6.5;
	h = 3;
	w = 7.5;
	w2 = 10;
	for (y = [h+m/2, h+oh-m/2]) {
		for (x = [-ow/2+m/2, ow/2-m/2]) {
			translate([x, y, -through/2]) {
				cylinder(d=m, through);
			}
		}
	}
	for (y = [h+oh-m/2]) {
		for (x = [-ow/2+m/2-w2, ow/2-m/2+w2]) {
			translate([x, y, -through/2]) {
				cylinder(d=m, through);
			}
		}
	}
}

module bar() {
	w = 100;
	h = 10;
	t = 2;
	r = 2;
	d = 28-t;
	d2 = d+5;
	translate(centerx(w)) {
		hull() {
			translate([r+d2, r, 0])
				cylinder(r=r, t);
			translate([w-r-d2, r, 0])
				cylinder(r=r, t);
			translate([0, d-r, 0])
				cube([r, r, t]);
			translate([w-r, d-r, 0])
				cube([r, r, t]);
		}
	}
	translate([0, d, 0]) {
		translate(centerx(w))
		cube([w, t, t+2]);
	}
}

module assembly() {
	module cutout() {
		midmounts();
	}
	difference() {
		bar();
		cutout();
	}
}

assembly();