[Heathkit] removing LMO knob on SB series radio

[Gerry Steffens]

OK.  So somebody took a pipe wrench to the hex wrench when they assembled
this equipment.  They tightened the LMO knob so as to hold off a herd of
charging elephants!  Or, is this the result of flowing aluminum coupled with
corrosion?  Everything appears clean & shiny.

Now, I want to take the LMO knob off.  I have the appropriate hex wrench.
To get down in to the set screw I must put the long end down into the knob.
My fingers can't turn the wrench without filleting my fingers.

Is there a secret to undo this without wrecking things?  Dare I use a pliers
or other tool on the wrench?

Any suggestions would be most appreciated.

TIA

Gerry