infty=200;
eps=0.01;

bar_diam = 20;
body_h = 15;
body_l = 100;

wall = 1.5;

spike_w = 1;
spike_l = 2;

module spike() {
	hull() {
		translate([-body_h/4, 0, -eps])
			cube([body_h/2, bar_diam/2+wall/2, eps]);
		translate([-spike_w/2, 0, -body_h/2])
			cube([spike_w, bar_diam/2 + wall + spike_l, eps]);
	}
}

difference() {
	union() {
		translate([-body_l/2, 0, 0])
			rotate([0, 90, 0])
				cylinder(r = bar_diam/2 + wall, h = body_l);
		for (x = [-37.5:15:37.5])
			translate([x, 0, 0]) spike();
		for (x = [-45:15:45])
			translate([x, 0, 0]) scale([1, 1, -1]) spike();
	}
			
	// tube hole
	translate([-body_l/2-eps, 0, 0])
		rotate([0, 90, 0])
			cylinder(r = bar_diam/2, h = body_l + 2*eps);
	// cut the bottom
	translate([-infty/2, -infty/2, -infty-body_h/2]) cube(infty);
	// cut the bottom
	translate([-infty/2, -infty/2, body_h/2]) cube(infty);
	// cut the bottom rear half
	translate([-infty/2, -infty, -infty/2]) cube(infty);
}