[Elecraft] Concentric knobs??

[Vic K2VCO]

This happened more than 30 years ago so I can tell the story. I worked at a kibbutz 
factory in Israel where we made plastic faucets by injection molding. The correct 
adjustment of the temperature profile of the molding cycle was critical to many 
characteristics of the finished parts.

Our engineer was going to Germany to demonstrate some products, so we carefully tested his 
samples so that he would not be embarrassed in front of the quality-conscious Germans.

At the demonstration, he turned the knob on the hot-water side of the faucet: snap. Then 
he tried the cold-water side: snap. Both stems broke off neatly inside the faucet!

The German engineers were not amused. Ultimately we learned how to adjust the molding 
machines properly!

On 6/24/2011 7:12 AM, hb9ari wrote:
> Hello Guy,
>
> I think that you have found the good explanation!
>
> May be some of these knobs don't get a correct or sufficient  pre-aging (?)
> procedure before leaving the factory; at my QRL pro, we get this kind
> of problem with molded plastic enclosure breaking some time after
> they were bee assembled.
>
> In French, we are speaking of "retrait" but i don't find
> the correct translation!
>
> My best 73,
> Rudi, HB9ARI

-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/