From Veeduber@aol.com  Wed Oct  4 23:13:26 1995
msgnum: msg17008
Date: Thu, 5 Oct 1995 00:13:18 -0400
From: Veeduber_at_aol_dot_com
Subject: Grendel, Wednesday



They have crows up there the size of chickens, and thick furred cats that
have never heard the howl of a coyote.  A blue-eyed seal-point spent the day
with me, oblivious to the whine of the drill and a muttering of curses when
the point would dull or break, as they all eventually did.  Six drill bits to
complete the cuts, carefully photographed now that I've learned Web Page
Richard can handle photos as well as text.  Most folks don't believe you can
cut a slot with a drill.  Been there, did that.  Got the T-shirt.  But didn't
remove the drum.

About five this afternoon as I started a row of holes intending to split the
entire drum top to bottom, my host's neighbor, a nodding acquaintance after
nearly three weeks, peered over the fence and said "If you're trying to split
the drum, I've got something that may be faster than drilling."  A nearly new
Makita 4" grinder.  I was wearing a 32-tooth grin when I snatched the thing
from him, plugged it in and began to slice cast iron.

I used up his grinding disk, will be down at the hardware store at the crack
of eight for another, should have the drum turned into scrap metal by noon,
mebbe sooner.  And no, he can't renig on the deal, I've got the grinder right
here beside me.

In case you've been wondering about this drum-splitting business, it's
possible to lock a drum to a stub axle simply by over-torquing it.  The drum
is made of a marvelously soft mallable cast iron, wizard stuff for generating
friction and soaking up heat without undue distortion.  It is the kind of
cast iron with big, chubby hunks of pure iron bound together with thin veins
of carbon.  It will bend before it will break.  And it will flow if over
torqued.  If it flows into the splines, it can lock itself to an axle so
strongly that nothing sets if free short of fire.  Or chopping the drum into
segments and taking it apart like a grapefruit, which is what I proceeded to
do with my drills and drill motor.  But there's more to it than drilling.
 The real trick is knowing where to drill.

The outer hub of the brake drum slopes down to an elongated hub.  Inside the
brake drum there is a similar hub but no slope; the inner hub is about an
inch long, the outer more than twice that.  Between the two is a thick web of
metal about 1-1/2" thick at the splined bore, thinning to about 1/4"
thickness everywhere except for the rim of the brake drum, which starts out
being over 1/2" thick.

To drill a drum free of the axle you must drill not only the outer hub but
the inner, the one you can't see.  To insure you cut the inner hub you begin
at the outer hub, drilling a small horizontal hole as deeply as you can and
as nearly parallel as possible into the meat of the hub.  When you've drilled
full-depth for your particular drill you go up a size or two until you arrive
at 1/4" diameter.  Then you switch to an 'aircraft' bit, a longer than normal
drill bit, and continue until the feel of the bit tells you it has found the
spacer ring, which is too hard to be drilled.  

This 1/4" diameter tunnel is the key to unlocking a frozen hub.  You must
drill four of them, all very nicely straight.  You drill them in pairs about
an inch apart on opposite sides of the hub, your goal being to remove the
metal between the twin tunnels.

The easy way to remove the chunk of metal is to drill a series of small holes
down to the 1/4" main tunnel.  Since the surface of the hub has a pronounced
curve you must drill your holes at an angle.  But since the goal is the
straight tunnel, and the starting point an inside curve, each hole is
actually the entrance to up to four drillings, each one angled slightly,
relative to the others, the object to remove as much metal as possible.

As your drilling progresses down the slope toward the threaded end of the
axle, you begin drilling horizontal holes into the drum, starting the bit in
each of the hole-craters you've just created.  If you keep everything aligned
the horizontal hole will encounter each of the angled holes you've drilled,
allowing you to keep track not only of what you've drilled but where.

Eventually you will arrive back where you started, at the outboard end of the
hub.  That's when you begin using your drill bit as an side-mill and your
drill motor as a milling machine.  You are the controller and vise.  It is
not a task for the highly strung.  By running the drill motor at top speed
and slowly changing the angle of the bit, the side flutes will shave away the
cast iron between the holes.  Do it wrong and you'll snap the drill, leaving
it embedded in the metal, blocking further chances to drill through that
level.  This is one of those procedures that is more difficult to describe
than to do, which is why I took a number of pictures.

Eventually you will achieve a pair of square-sided grooves in the hub of the
brake drum.  The metal won't fall out in your hand because of the hundred or
so webs remaining between the angled and horizontal holes you've drilled;
your grove can only extend to the exposed portion of the hub since you must
have room to lever the drill motor back and forth.  For the inner hub, the
available range of motion is too small to cut a complete grove, you will end
up with a tunneh having a curtain of walls, the residue of your angled
drillings.  To defeat these remaining webs you drive a cold chisel into one
of the groves.  The chunk of metal will bend toward the other groove,
fracturing some of the webs.  Now do the same thing to the opposite groove.

It will take about a dozen hammerings of the chisel in each of the grooves,
working the hunk of metal back and forth but eventually the chunk of metal
will snap free.  If luck is on your side the missing lump will extend
entirely through the hub.  You can then break the grip of the splines using
heat and hammer blows, or apply a regular puller, the missing metal having
made the thing a sloppy fit on the axle.

And then there are days like today, in which the chunky did not break cleanly
through to the inner hub.  It broke about three-quarters of an inch short,
leaving me to figure out how to get rid of the chunkie, since the hub will
remain locked to the axle so long as ANY of the inner hub remains.

I managed to leave chunkies in both cuts and was out of sharp drills, gnawing
at he remaining half-inch of cast iron with a quarter-inch drill bit that I
eventually broke.  About then the neighbor leaned over the fence, I did a
couple of cartwheels across the alley and began to burn the cast iron drum
away in a shower of orange sparks.  I ground on the drum until the disk could
not make contact with the metal.  It was about seven pm.  I'd been at it for
ten hours.

I'll be back tomorrow and THEN watch those sparks fly.

-Bob