//Disable $fn and $fa, do not change these $fn=0; $fa=0.01; $fs=0.5; m2=3.0; module nut() { rotate([0,0,30])cylinder(3,r = 5.5 / 2 / cos(180 / 6) + 0.2, $fn=6); } length=50; width=8; height=8; difference() { cube([width,length,height]); translate([width/2,4,0])nut(); translate([width/2,length+1,4])rotate([90,0,0])nut(); }