[Elecraft] Split knob question

[WILLIS COOKE]

I have had numerous knobs split.  None of them split while I was moving the set screw or even shortly thereafter.  Most split after months of use and with no specific event happening other than moving the gain setting.  The last set of knobs received about 5 or 6 months ago and supposedly with a new formula for the plastic are still hanging in there but I am still keeping the old knob from a defunct CB talkie so I at least have an audio gain.  I am convinced that the problem is/was in the plastic mix and that Elecraft has done what is in their power short of buying a more expensive aluminum knob set.
 Willis 'Cookie' Cooke 
K5EWJ 




________________________________
From: Ken Kopp <k0pp at rfwave.net>
To: elecraft at mailman.qth.net
Sent: Sun, May 9, 2010 1:18:46 PM
Subject: [Elecraft] Split knob question


If someone has a split knob in hand, please look
closely at the tapped hole. Since there seem to
be so many knobs splitting, I'm wondering if the
manufacturer has inadvertently tapped the screw
holes with a taper tap and not with a bottom tap,
as should be the case.  

There are three degrees of tap taper in common use.
The bottom tap is straight and obviously produces 
straight threads, but it's not as easy to start straight.

A set screw screwed into a hole threaded with a taper
tap would force the knob apart and might be the cause
of the splitting.

73! Ken Kopp - K0PP
    ElecraftCovers at rfwave.net






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