include rotate([0, 90, 0]) difference() { // Main Block cube([side_size_x, side_size_y, side_size_z], center = true); // Cut Holes for (z = [-1:2:1]) { translate([0, 0, z * side_size_z/2]) cylinder(h = thread_insert_z * 2, d = thread_insert_dia, $fn = seg, center = true); } }