infty=200;
eps=0.01;

bar_diam = 20;
body_h = 7;
body_l = 150;

wall = 1.5;

spike_w_bot = 1;
spike_w_top = 6;
spike_l = 5;

spike_count = 8;
spike_dist = body_l/(spike_count + 1);

module spike() {
	hull() {
		translate([-spike_w_top/2, 0, body_h/2-eps])
			cube([spike_w_top, bar_diam/2+wall/2, eps]);
		translate([-spike_w_bot/2, 0, -body_h/2])
			cube([spike_w_bot, 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 (i = [-spike_count/2:1:spike_count/2])
			translate([i*spike_dist, 0, 0]) 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 top
	translate([-infty/2, -infty/2, body_h/2]) cube(infty);
	// cut the rear half
	translate([-infty/2, -infty, -infty/2]) cube(infty);
}