It's useful to remember that a screw (or bolt) is a spring. When tightened it stretches lengthwise. Like any spring, it offers the best "grip" when subjected to the right range of pressure.
Way back in my High School days (1950's - before Mercury was a toxic substance) I watched a demonstration using a bolt and nut made of frozen Mercury. Mercury is not elastic. Liquid Mercury was poured into molds for a nut and bolt and hardened with liquid nitrogen. Using gloves, the demonstrator assembled the nut and bolt using a large wrench to apply a great deal of torque. That done, anyone could loosen it without a wrench by just twisting the nut or bolt with minimal finger pressure (inside the gloves of course). There was no resistance since Mercury does not stretch. It's easy to over torque (stretch) small screws. That's why the Elecraft kit assembly manuals do not recommend using power screwdrivers. The Elecraft factory in Watsonville is equipped with special torque-limiting power screwdrivers to allow quick assembly with screws not so tight they are damaged or broken. Since a screw is basically an inclined plane that stretches the screw when tightened, vibration will allow the screw to turn (slide along the plane of the threads), hence the use of lock washers or chemical compounds in such environments to stop any movement. Perhaps the issue with the KX2 paddles is the vibration as the contacts collide allowing the screws to turn. Working remotely on the Elecraft manuals I've not been directly involved with the issue, so that is pure speculation. 73, Ron AC7AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
