"Paul P" REMOVE paul @ REMOVE ppinyot . REMOVEcom wrote in
message ...

Product Linear Temperature Expansion Coefficient - ?-


(10-6 m/m K) (10-6 in/in oF)
Aluminum 22.2 12.3
Steel 13.0 7.3

from:
http://www.engineeringtoolbox.com/li...ents-d_95.html


Looks like the aluminum will expand greater than the steel
when both are equally heated.


Paul P.
Now, does the expansion of the knob make the hole larger
or smaller? My instinct is that all dimensions get larger,
hence the screw should be looser. Or maybe the answer is
some dry ice or liquid nitrogen. (That's only half kidding).


--

--
Richard Knoppow
Los Angeles
WB6KBL

Now, does the expansion of the knob make the hole larger or smaller? My
instinct is that all dimensions get larger, hence the screw should be
looser. Or maybe the answer is some dry ice or liquid nitrogen. (That's
only half kidding).

Richard Knoppow
Los Angeles
WB6KBL


I think that since the metal shrinks when colder, an inside diameter will
get larger and an outside diameter will get smaller too. It's all
shrinking, not collapsing on itself.

Barry - N4BUQ

It is probably so galled that you won't get it off without having to retap
anyway. Too bad you can't just work around it.

Bummer

On Jan 13, 9:11*pm, "JB" wrote:
It is probably so galled that you won't get it off without having to retap
anyway. *Too bad you can't just work around it.

Bummer



-- 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

No wonder the wrench bent ! .. you need to heat the alloy knob with
the heat gun .. as hot as you can get it .. with the hole to the top
so you can drip some thin oil in ... then if you like chill the
wrench ... and have a go ... your lucky the hex key still gets a
grip .. ....

need alloy as hot as possible
screw as cold as possible

slight nip clockwise first may break the bond

G ..

Graham wrote:
JB wrote:
It is probably so galled that you won't get it off without having to retap
anyway. Too bad you can't just work around it.

Bummer



-- 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

No wonder the wrench bent ! .. you need to heat the alloy knob with
the heat gun .. as hot as you can get it .. with the hole to the top
so you can drip some thin oil in ... then if you like chill the
wrench ... and have a go ... your lucky the hex key still gets a
grip .. ....

need alloy as hot as possible
screw as cold as possible

slight nip clockwise first may break the bond

G ..

Dunno if this'd work but, Locktite "High Strength Thread Locker" is pretty
strong stuff. It's strong enough to lock the ½" diameter engine cylinder
head studs in my racecar's engine. Perhaps you could "glue" the Allen
wrench into the setscrew (being careful to not get any on the threads), let
it cure overnight, and try breaking the screw loose afterward. See
http://tinyurl.com/9zvre5 to see which one might be "bestest". Poor quality
(soft alloy steel) Allen wrenches will twist/bend... start with a good
quality Allen Wrench. Use heat to release the thread locker. If *that*
won't do it, I think you'll be drilling the screw out and retapping to the
next larger size.

vy 73,
Bryan WA7PRC