On Sat, 24 Sep 2011 20:19:31 -0700, Bill
wrote:

On 9/24/2011 6:42 PM, wrote:
On Sat, 24 Sep 2011 21:21:26 -0400, "Phil Kangas"
wrote:


wrote in message
...
On Sat, 24 Sep 2011 14:47:44 -0400, "Phil
Kangas"
wrote:


wrote in message
...
Here is what I'm working on.

http://s1123.photobucket.com/albums/...t=IMG_2610.jpg

1964 garden tractor. The wheel hub must come
off
before the brake
linkage can be removed before the transmission
can be removed, etc.

The hub is cast about 3/8 thick. The brake
drum
is bolted to the back
of it so there is no place to hook a puller or
anything like a bearing
separater. The lug bolt holes are the only
pulling points (5 on
4.5"). Problem is the 5/16 set screw.

I've tried drilling them out with what I
thought
were pretty good
bits. I'm barely knocking the rust off. They
are
hard. I've used an
allen impact driver to no avail. (good part is
they don't strip out)
There is enough meat to redrill and tap to
larger size.

I can apply limited heat but don't want to be
looking for nonexistant
axle seals.

Once the set screw problem is solved, I can
(reluctantly) drill and
tap pulling holes closer to the 1" axle.

This photo looks dry but it has been flooded
with JB Blaster for two
months. An additional consideration is this is
one of only two
surviving. Suggestions?

My first choice would be heating with a TIG
torch.
Concentrate on
the set screw and get it hot, red hot if you
can.
There is enough
mass of iron there to save the seal if you stay
on
the screw. After
it cools to about 300 to 400 deg apply 50/50 atf
and acetone. Make
no attempt to turn it till it completely cools
off! When the screw is
heated it will try to expand but it cannot and
when it cools it will
shrink to allow turning. HTH....
If you don't have TIG then try an oxy acet gas
welding torch,
single flame. Stay on the screw.... oh, I
already
said that....
phil k.


I have a couple of O/A torches. Do you think
heating the screw will
change the hardness enough to be able to drill
it?

It is in at an angle so only one edge is
contacting the key. If I can
drill it, I think that thin edge might bend or
break off when pulling
the hub off.

Heat will soften it. Try a smaller drill first,
stepping up in size.
It may be possible that the screw is in a shallow
hole in the key.
That would secure the key from working out in
service. Something
to consider anyway.
phil k.


Many set screws actually harden with heating - from my experience

if it were me, I'd use Kroil for a bunch of days, then I'd heat the hub
and when it is hot (but not glowing), I'd put a hex key in the set screw
and loosen it (or if it's not a hex key, use whatever fits it) - the
heat will expand the hub and tend to soften/break down the rust. If
that doesn't work, let it cool and repeat with more kroil, some time,
and try again

Something Ive had recent experience with is a standard motorcycle impact
driver with an allen wrench socket. Used a moderate sized hammer after
Kroil and heating..and turned out the setscrew fairly easily, one tap at
a time.

So Ive now stocked up on allen and torx sockets and picked up another
couple motorcycle impact drivers and put them in my service trucks for
this sort of thing.

Old tech..but still works.

Gunner

"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)