Many ARF's come with metric rod and are slightly smaller. Like horace said Do not use 2-56 roll threaded metal clevis with these. Actually many of the plastic clevis are fine with the best quality being great plains or Dubro as well as some others. People tend to get unreasonably paranoid about plastic clevis when in reality the rolled and folded steel types comes with their own set of failure modes that plastics do not. These can over time from vibration and use can open the fold slightly and strip threads.

Whatever you choose to do, never ever use a steel clevis on a metal throttle arm (most are metal) or for that matter an easy just or S bend this is a frequent cause of mystery radio failures from vibration induced stray RF noise.

John