Now available is the Control Rod Rigger, a new tool that allows mechanics to duplicate the length of any AN-3 through AN-6 control rod to ± .005 when changing worn rod ends.
Using this tool will eliminate poorly measured control rods requiring aircraft re-rigging, said company officials, who note “the tool is easy to use, and satisfaction is guaranteed.”
.005 is less than a 1/2 flat turn for AN-4 and bigger control rods. This accuracy is useful when adjusting helicopter rotor heads. For reference, a MSC 24″ Value Vernier Caliper cost is $287. The Control Rod Rigger will do a better job and it is easier to use. When you measure the inside or outside of the bore of the old rod ends with a caliper, the setting will include the wear. If you measure to the outside of the rod end housings, that housing diameter tolerance is ±.010. With the Control Rod Rigger, well worn rod ends will center up by pushing down on the rod as the tool is adjusted. If you count threads or turns when removing the old rod end, the tolerance on thread length to ball center is ± .032. Using a tape measure or mark on a board would not result in a precision measurement.
To use this tool to adjust twisted control rods, rotate one rod end counter-clockwise until the control rod is flat and can fit on the tool. After replacing both rod ends, rotate the same rod end clockwise to the proper angle. Do not switch rod ends or direction when turning to the proper angle or you will have the wrong length. I recommend rotating the right hand threaded rod end every time for consistency. Do it the same way every time.
The 24″ Control Rod Rigger lists for $145.
For more information: PropPastie.com