[R-390] R390 knob set screw

[John KA1XC]

Just remembered another quick fix......
Try wrapping a layer or so of plumbers Teflon pipe thread tape tightly over
the setscrew, it'll build up its diameter and make it fit tighter.

John

> Dan,
> my notes say it's 8-36 UNF thread, yet another oddity of the 39x's. If you
> had the tap you could epoxy the hole and drill and retap it but a
> replacement knob can be gotten cheaper.
>
> Sometimes you can smear some JB Weld across just the damaged area, let it
> firm up a bit, and then use the setscrew itself as a tap, then remove it
and
> let the JB cure. If your lucky it can give the setscrew the little extra
> bite it needs to do the job.
>
> That phenolic insulating shaft on the 390 is pretty tough, I wouldn't
worry
> too much about hurting it.
>
> John
>
>
> ----- Original Message ----- 
> From: "Dan Merz" <djmerz at 3-cities.com>
> To: <r-390 at mailman.qth.net>
> Sent: Thursday, April 14, 2005 12:22 AM
> Subject: [R-390] R390 knob set screw
>
>
> > Hi,  I ran into a minor problem.  The set screw in one of the larger
knobs
> > (on the ant trim on R390) doesn't want to tighten against the shaft and
I
> > see that the threads in the knob are damaged in the area near the shaft
> and
> > the screw likes to just ratchet back at the critical point of
tightening.
> > It's the knob not the set screw that's the problem.  I think a longer
set
> > screw of 3/8 length would solve the problem.  What is the thread
> size/pitch
> > on these set screws? I make it to be 8-36, an unusual size these days.
> Are
> > there some screws longer than the standard 1/4 inch length in somebody's
> > pile?  The other alternative is to drill and tap it for the next larger
> size
> > set screw but who wants one knob to have a different size wrench, hi?  I
> > guess I could shove a piece of solder or piece of plastic in front of
the
> > short one and hope for the best.  The trimmer shaft looks like phenolic
so
> > I'd like to treat it nicely.  Any advice on fix appreciated,  more
later,
> > Dan.
> >
> >
> > _____________________________________________________________
> > R-390 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/r-390
> > Help: http://mailman.qth.net/faq.htm
> > Post: mailto:R-390 at mailman.qth.net
> > Unsubscribe: http://mailman.qth.net/mailman/options/r-390
> >
>
>
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>