For my metal rod connections, I have both a threaded clevis, and a soldered clevis. I don't need to thread anything. I thread the metal clevis on the servo end, and the other end, I use a solder clevis. That is, once measured, adn all is 'straight', I cut it to length, and then solder it on. Sullivan and Du Bro both make 'solder celvises'. You'll need to pick up a small torch, some plumbers flux, and solder. Acetone will clean it all up in a jiffy!

One 'danger' about using threaded clevises on both end is that you have to 'lock' one end so the rod does not turn / rotate. As you turn teh rod (due to vibrations), it'll unthread in one clevis, but thread in on the other.