The K3 manual emphasis over and over to avoid "over tightening" screws. Corresponding with many builders, it seems clear that they don't realize that parts "screwed together" are actually held together by a stretched spring attached to them. When a screw is threaded into a nut, the inclined plane of the threads pulls the nut and screw together until they meet, then further turning literally stretches the screw lengthwise.
On large parts (like a building or bridge) designers provide torque values that must be used to insure just the right amount of "stretch" for the most secure assembly. On small parts, like the Elecraft rigs, the actual torque isn't real critical but, within the broad range permissible, using the right torque is still important. Don't just twist as hard as you can. Always consider the materials you are fastening. Once the surfaces mate and you feel the torque needed to turn further increase quickly, only a small amount of additional torque is wanted to "set" the spring action, depending upon the material involved. Forcing the screw beyond that point only puts unnecessary strain on it and the parts you're fastening. Use a little too much torque and the screw shaft breaks because you stretched it too far or you destroy the inclined plane (strip the threads). If you're fastening a not-so-strong material like plastic or pc boards, you can damage the plastic or board by crushing the material. The bottom line is that when it comes to tightening screws, "more" torque is definitely not "better". It's often far worse than "not enough". Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
