infty = 100;
eps = 0.01;

wheel_d = 60;
wheel_h = 4;
wheel_thick = 1;

spokes = 5;
spoke_w =  5;
spoke_h = 3;

center_d = 8;
center_hole = 3;

module body() {
	// rim
	difference() {
		cylinder(r = wheel_d/2, h = wheel_h, $fn = 128);
		translate([0,0,-eps])
			cylinder(r = wheel_d/2 - wheel_thick, h = wheel_h + 2*eps);
	}

	// spokes
	for (a = [0:360/spokes:360-eps]) {
		rotate([0, 0, a])
		translate([2, 0, 0])
		hull() {
			translate([-spoke_w/2, 0, 0])
				cube([spoke_w, wheel_d/2 - wheel_thick/2, eps]);
			translate([-eps/2, 0, spoke_h-eps])
				cube([eps, wheel_d/2 - wheel_thick/2, eps]);
		}
	}

	cylinder(r = center_d/2, h = wheel_h);
}

difference() {
	body();
	// center hole
	translate([0, 0, -eps])
		cylinder(r = center_hole/2, h = wheel_h + 2*eps);
}