handling_dia = oring_bore + oring_thick*2 + min_wall*2;
handling_angle = 45;
-sm_inner_rad = sm_inner_circum / TAU;
+sm_inner_rad = (sm_inner_circum + sm_bolt_tighten_allow/2) / TAU;
sm_outer_rad = sm_inner_rad + sm_main_thick;
smc_pos = [ 0, sm_inner_rad, 0 ];