"Jeff" wrote in message
...
I need to remove an aluminum knob from a radio, but the
Allen setscrew
is stuck solid.

I've tried:

-- WD-40
-- Kroil
-- an Allen wrench with a long handle (bent handle)
-- an Allen 1/4" drive socket (twisted the Allen part)
-- blocking up the knob with rubber blocks and beating on
the Allen
wrench while turning
-- heating the Allen wrench with a heatgun while engaged
with the
setscrew and turning
-- heating the Allen wrench to 450 degrees and then
inserting it into
the setscrew and turning

All this and the bloody thing is still stuck solid. As a
last resort
I know I can drip 1-mole nitric acid into the hole, which
would eat
the steel setscrew and leave the aluminum relatively
untouched. This
I have done on aluminum car engines with snapped-off
manifold bolts
and it works great.

However, I can think of a bunch of ways this could go
wrong when
applied to a rare radio.

I would greatly appreciate any ideas.

Thank you.

73,
Jeff
N6MNI

Don't know a sure cure other than drilling out the set
screw. Heating the set screw will make things worse by
expanding the screw. heating the knob may help. Also, I've
found that Liquid Wrench works sometimes where WD-40 does
not. It may take a week or two for the oil to penetrate. Put
a new application on every day.
Aluminum tend to gall, this may have happened here. The
result is pretty tight sticking. If you succeed in removing
the screw the new one should have a bit of anti-galling
compound on it. I think you can get this at most hardware
stores.


--

--
Richard Knoppow
Los Angeles
WB6KBL