"Joseph Gwinn" wrote in message
...
So, after implementing the ridged plate with index-pin hole to keep the
Dickson-style toolpost from rotating while performing cutoffs, and using
a 0.5x0.5" HSS tool (versus 0.25x0.25), everything was peachy until I
tried to take a cut 4" from the chuck in a mild steel bar 1-3/8" in
diameter. What a noise that made. The entire lathe shook. Even with
fairly shallow cuts. The tailstock chuck fell out of the tailstock
taper (no harm done). And the tool-slide (upper) handwheel started to
turn by itself. It was always too easy to move, and I had noted that
the reduction in work piece diameter did not match the change in
cross-slide (lower) handwheel position. Hmm. I bet it's creeping, even
when not obviously moving.

The gib between tool post slide (Clausing part number 704-033, page 30)
and the top of the compound (704-034) is the one I could not adjust, for
unknown reasons.

So, I disassembled the upper assembly, the thing that rotates to set the
cutting angle. As expected, it was pretty dirty, and there were signs
that it had been partially wet at one time.

One of the swivel bolts (055-017) had been stretched by too forceful
tightening. Filed the top off a bit so it wouldn't pinch against the
underside of the compound slide and break that thin cast-iron web. I'll
have to make a new swivel bolt.

The two 10-24x 5/8" hex socket cap screws that attach the dial hub
(382-029) to the tool post slide were mangled -- it seems that the holes
were not tapped deeply enough, or the screws were too long, but the
screws were driven home anyway. So, re-tapped the holes, and
re-threaded the cap screws.

It took some careful tapping with a drift, but got the gib (345-023) out
without difficulty. Apparently, some prior owner did not understand how
to use the gib adjusting screws (696-089) - loosen one before tightening
the other, and managed to break the critical corners of both ends of the
gib off, leaving ramps. It must have taken considerable force. So,
when one tightened the make-tighter adjuster (next to the dial hub), it
instead pinched the gib against the wall. The gib is also unevenly
worn. And was loose. So, after filing some upset areas down, turned
the gib over. It isn't perfect, but it will have to do for now.

I suppose one can make a gib by hand, although a surface grinder would
come in real handy. Two surfaces are parallel, while two taper towards
one another at a shallow angle, and the cross section is always a
trapezoid.

Anyway, put it all back together with nice clean Mobil 1 grease on the
tool post screw and thrust bearings (no oil ports for these), and Vactra
#2 way oil everywhere else, and got the tool post slide tight enough so
it does not move by itself.

Fortunately, the larger cross-slide gib (345-022) does not appear to
have been butchered. I have not yet taken that whole assembly apart,
but I have taken the cross-slide off the saddle, removing, cleaning, and
adjusted the gib.

My suspicion is that the water caused rusting of ways, and the problem
was solved with muscle, not brain.

Anyway, all this helped a lot, and I made the first part, a collar for
use in the toolpost.

Cutting that steel with a big carbide-tipped bit was absolutely
peaceful. It made hardly any noise as the chips curled off by the foot,
and left a very nice surface. I wonder if the steel was leaded. It
came with the lathe, and was rusty as hell. But it was soft to the
file, even where there had been a welding puddle, so I went ahead and
used it.

Now, I get chatter if I try to take a 0.030" to 0.050" cut with the
carbide tool, which has a nose diameter of something like 0.100" (which
is large). My question is how heavy a cut I should be able to make on
this lathe, to have some idea when I have succeeded is solving the major
problems.

Joe Gwinn

The depth and feed of any given cut will hinge a great deal on the power and
rigidity of the machine in question, but you can take this to the bank::
stay away from large radius tools unless they are absolutely necessary.
Anything beyond 1/16" is asking for grief on light duty machines, which
would include the Clausing. Mind you, I'm thinking of machines similar to
a Mori-Seiki, Axelson or Monarch when I judge the Clausing. I'm not
implying it's not a decent machine. It is-----it's just not heavy duty, and
not well suited to running form tools.

I might suggest that you may be able to pull a cut of .100" depth per side,
with .010" feed when roughing, in steel. Could be wrong. All depends
on how tight the machine is, and if you have the horsepower, as I stated.
I can reduce 3" steel @ .200" per side, .012" feed, negative rake, with my
3 hp Graziano Sag 12.

Harold