infty = 100;
eps = 0.01;

diameter = 25;
thick = 2.5;
base_thick = 1.5;
d_minus = thick; // cca 45 deg

center_hole_d = 3.5;
side_holes = 5;
side_hole_d = 5;

cut_hole_d = 2;
cut_slot = 1;

module body() {
	cylinder(r1 = diameter/2, r2 = diameter/2-d_minus/2, h = thick/2 + eps);
	translate([0, 0, thick/2-eps])
		cylinder(r2 = diameter/2, r1 = diameter/2-d_minus/2, h = thick/2 + eps);
}

difference() {
	body($fn = 128);
	translate([0, 0, -eps])
		cylinder(r = center_hole_d/2, h = thick + 2*eps, $fn = 128);
	if (side_holes > 0) 
	for (angle = [0:360/side_holes:360]) rotate([0, 0, angle+180/side_holes])
		translate([diameter/3 - d_minus + center_hole_d/2, 0, -eps])
			cylinder(r = side_hole_d/2, h = thick + 2*eps, $fn=128);
	if (base_thick)
		difference() {
			translate([0, 0, base_thick])
				cylinder(
					r1 = center_hole_d/2 + base_thick,
					r2 = diameter/2-d_minus/2,
					h = thick-base_thick+eps, $fn = 128);
			translate([0, 0, base_thick-eps])
				cylinder(r1 = center_hole_d/2 + base_thick,
					r2 = center_hole_d/2 + base_thick/2,
					h = thick - base_thick + eps, $fn = 128);
		}
	if (cut_hole_d) {
		translate([diameter/3-cut_hole_d/2, 0, -eps])
			cylinder(r = cut_hole_d/2, h = thick + 2*eps, $fn =128);
		translate([diameter/2-d_minus/2, -cut_slot/2, -eps])
			cube([diameter/2, cut_slot, thick + 2*eps]);
	}
}