[R-390] R-390 Digest, Vol 103, Issue 14
Glenn
wa4aos at aol.com
Thu Nov 15 13:39:09 EST 2012
Problem: Bristol setscrew appears to be welded to the control shaft.
How to loosen it up?
I am afraid to twist any harder for fear of breaking my Bristol wrench.
I have had this problem many times. Seems some of these knobs were reset with Lock-Tight.
Of course try the suggestions provided but if it still want budge this is what I do.
I made an 2.5 x 2.5 inch aluminum plate with a large slit in the middle for the knob shaft to go. I placed double Thin double stick tape on the back side and seat the plate behind the knob. Then use two straight screwdriver blades in opposing force and the knob will slide off; easily most of the time. Of course you don't have to make a protector plate but you may end up with a few small gouges in the aluminum panel. I have also used 2 screwdrivers with the ends dipped in liquid plastic to prevent marring without the plate. I just prefer not having 2 tools tied up for 1 dedicated task.
You may have to debur the shaft with sand paper afterwards from the sliding but this is easy too.
Good luck,
Glenn WA4AOS
DSM Labs (dot com)
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Today's Topics:
1. Fundamental question - setscrews (John Saxon)
2. Re: Fundamental question - setscrews (Mike A)
3. Re: Fundamental question - setscrews (Don Reaves)
----------------------------------------------------------------------
Message: 1
Date: Wed, 14 Nov 2012 09:45:27 -0800 (PST)
From: John Saxon <johnbsaxon at yahoo.com>
Subject: [R-390] Fundamental question - setscrews
To: r-390 at mailman.qth.net
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<1352915127.50379.YahooMailClassic at web160401.mail.bf1.yahoo.com>
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Another simple question...
Straightforward goal: remove a knob
Problem: Bristol setscrew appears to be welded to the control shaft.
How to loosen it up?
I am afraid to twist any harder for fear of breaking my Bristol wrench.
Suggestions?
Thanks,
John
K5ENQ
------------------------------
Message: 2
Date: Wed, 14 Nov 2012 13:13:15 -0600
From: Mike A <mikea at mikea.ath.cx>
Subject: Re: [R-390] Fundamental question - setscrews
To: r-390 at mailman.qth.net
Message-ID: <20121114191315.GC39705 at mikea.ath.cx>
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On Wed, Nov 14, 2012 at 09:45:27AM -0800, John Saxon wrote:
> Another simple question...
>
> Straightforward goal: remove a knob
>
> Problem: Bristol setscrew appears to be welded to the control shaft.
>
> How to loosen it up?
>
> I am afraid to twist any harder for fear of breaking my Bristol wrench.
>
> Suggestions?
Apply a drop of penetrating oil, wait a few hours, try again?
If that still fails, then try alternating these:
o touch a hot soldering iron to the setscrew long enough to heat-soak
the metal; then
o spray the setscrew with some freeze spray or other -- say canned
air, upside down.
The idea is to try to break it free using thermal expansion and
contraction.
--
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin
------------------------------
Message: 3
Date: Thu, 15 Nov 2012 05:44:49 -0600
From: Don Reaves <donreaves at gmail.com>
Subject: Re: [R-390] Fundamental question - setscrews
To: R-390 List <r-390 at mailman.qth.net>
Message-ID:
<CAEjO2Lak6tEOcEu=ypaG5PR5uHBSqT329Kf3REkqY4HjD-HFUw at mail.gmail.com>
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It is counter intuitive, but I've had some success tightening a stuck screw
ever so slightly first to break the tension. Righty tighty, lefty loosey.
There must be some law of Newtonian physics that explains this phenomenon.
On Wed, Nov 14, 2012 at 1:13 PM, Mike A <mikea at mikea.ath.cx> wrote:
> On Wed, Nov 14, 2012 at 09:45:27AM -0800, John Saxon wrote:
> > Another simple question...
> >
> > Straightforward goal: remove a knob
> >
> > Problem: Bristol setscrew appears to be welded to the control shaft.
> >
> > How to loosen it up?
> >
> > I am afraid to twist any harder for fear of breaking my Bristol wrench.
> >
> > Suggestions?
>
> Apply a drop of penetrating oil, wait a few hours, try again?
>
> If that still fails, then try alternating these:
> o touch a hot soldering iron to the setscrew long enough to heat-soak
> the metal; then
> o spray the setscrew with some freeze spray or other -- say canned
> air, upside down.
> The idea is to try to break it free using thermal expansion and
> contraction.
>
> --
> Mike Andrews, W5EGO
> mikea at mikea.ath.cx
> Tired old sysadmin
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--
--
Don Reaves W5OR WD2XSH/15
8101 Barrett Rd. Roland AR 72135
VOIP landline: 501.420.3661
------------------------------
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