include ; long=100; shim=0.1; fudge = 0.3; bolt_r = 3.0+fudge; module fastener(between=20, w=35, h=12, th=3) { difference() { cornerless_cube(w, h, th, 5.0); translate([w/2-between/2, h/2, -shim]) cylinder(r=bolt_r, h=long, $fn=48); translate([w/2+between/2, h/2, -shim]) cylinder(r=bolt_r, h=long, $fn=48); } } fastener();