Originally Posted by aerosheldon
the one I quoted in the post… the bolt to spread the load
ah, the washers... if you use the standard gear of the 71/72 planes, they have a bolt and a locking nut. You can overtighten and split the control arm. If you use washers, this spreads the load of the tightened nut across the surface of the control arm making it all that much stronger when in use (the force from the control surface trying to twist the bolt in the arm, etc). I split one of the arms by overtightening... washer stops the overtightening and makes the result stronger.