//Disable $fn and $fa, do not change these $fn=0; $fa=0.01; $fs=0.5; module ring(r0) { d=r0-0.8; // was 0.5 rotate_extrude(convexity = 10, $fn = 100) translate([d, 0, 0]) intersection() { circle(r = 1, $fn = 100); translate([-2,-2])square(2); } } probe_inside_d=5.1; // 4.9 probe_inside_l=7.0; // 3.0 probe_t=1.6; probe_h=10.0; probe_flag_h=12.0; probe_flag_t=4; probe_flag_w=7.0; union() { translate([-probe_flag_w/2,-probe_flag_t/2,probe_h])cube([probe_flag_w,probe_flag_t,probe_flag_h]); translate([0,0,probe_inside_l])ring(probe_inside_d-1); difference(probe_inside_d) { cylinder(h=probe_h,d=probe_inside_d+2*probe_t); cylinder(h=probe_inside_l,d=probe_inside_d); } }