translate([tuberad, 0]) square(center=false, size=[mainthick,dy]);
FArcSegment(0, 0, tuberad, tuberad + clipthick, 360-clipang, clipang+1);
translate([tuberad, 0]) square(center=false, size=[mainthick,dy]);
FArcSegment(0, 0, tuberad, tuberad + clipthick, 360-clipang, clipang+1);