On 2008-05-07, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

And -- your compound has less adjustment range for the gib
because the dovetail itself is shorter, so the compound would show the
problems sooner, given equal wear.

It was the narrower dovetail width that matters, more so than the
length. On a narrower dovetail the same amount of wear in thousandths
allows for greater angular motion.

O.K. But you also probably don't have as much adjustment range
in the tapered gib so you can't tune out as much wear as you could in
the cross-slide.

[ ... ]

I did another experiment today, this time cutting 1018 steel with the
grooving tool with the flat nose 0.206" wide held upside down in a
toolholder and with the lathe in reverse, and the backgear engaged. I
can cut a wide groove without drama and in almost total silence (aside
for the noise of the gears), but the tool and toolpost rises visibly
under the strain.

O.K.

Now this is a very severe test, yielding chips about -0.008" thick by
0.200" wide, and involves very large forces, so the toolbit rising is
not a surprise. One has to push pretty hard before the tool starts to
bite with an audible bump, and it then yields the 0.008" thick chip. If
one maintains the pressure, one can make a very long and curly chip.

Yes -- though the long and curly chip when parting can be a
problem, because it can wedge in the groove and result in a broken
parting tool.

[ ... ]

I read in one of the Mac magazines that only 10% or 15% of Mac owners
use any kind of add-on anti-virus product, and the unprotected Mac
owners are none the worse for it, and have been for years.

Unix/Linux users have even less to worry about.

Yes -- though there is a tradeoff to being a user of the most
numerous unix version -- which I think is now Solaris 10. That makes it
the next likeliest target.

But it has not happened yet. And while Solaris isn't completely
hack-proof, it's orders of magnitude less vulnerable than Windows.

And I've also turned off quite a few things which I don't need
or want. And, at least in unix systems, it is fairly easy to learn how
to turn things off or on.

By contrast, an unprotected Windows machine on the web will last a few
days at most, and a dialup machine might manage months before getting
caught.

An unpatched Windows box, from first connection to the net in a
college dorm, has an expected mean-time-to-infection significantly less
than the time needed to download the patches via the net -- even with a
fast pipe. This is why at least some colleges (those who care about
security) will not connect a new box to the net until one of their staff
have come around with a DVD or CD containing all the patches and applied
them. This at least slows down the infection rate somewhat. :-)

A college dorm has to be some kind of worst case test.

Indeed so. Lots of machines in unskilled hands, tons of
bandwidth, so they can all be attacking each other. :-)

One very large problem in Windows is that one does not have to provide a
password to install most software,

And toss in the "have you forgotten your password? Would you
like to set another?" behavior, and ... :-)

while in MacOS and Unix, one does.
This sharply limits the growth rate of viruses as at ever step of the
way, a human is required. This prevention of automation is sufficient
to sharply reduce the prevalence of viruses in non-Windows platforms.

Indeed so.

Now, Microsoft is slowly changing Windows so people don't have to run
their software from an administrator account, but this is like turning
the Queen Mary. But it five or ten years it will have been done.

If they are still around by then. :-)

[ ... ]

Oh -- the thrust bearing was loose. On the cross-slide of mine,
the handcrank screws onto the leadscrew and then is locked by a cone
nut which goes into a countersink in the crank (IIRC). It is easy to
get this too tight. But it is also easy to tell that this is the source
of the play by feel. You feel a bit of a "thud" as the bearing play is
taken up, while the backlash in the actual leadscrew/net interface is
less sudden. :-)

The hand cranks are woodruff keyed to the screw shafts on the 5914, and
are kept on the screw shaft with a thread and cone nut as well.

I had to go back to the manual to make sure that I had
remembered it properly. It is a threaded collar of fairly small
diameter with a step towards the crank on which the dial slips and
rotates when the thumbscrew is loose. And yes, the collar *does* thread
onto the end of the shaft, with a nut which locks against that, and then
the crank screws on. But there is not the cone nut which I thought that
I remembered.

Before doing this, it helps to disassemble, clean, and lubricate the
entire dial assembly, so things can turn freely.

Of course.

Mine turned OK albeit with drag, and I worried that people might not
realize how much better it would work after a cleaning, in particular if
one wants to move the dial to a new zero without disturbing things.

Indeed -- and the drag for the crank actually helps avoid
disturbing the crank position while re-positioning the dial.

[ ... ]

The Nichols horizontal mill takes a lot less space than many,
and (usually) offers a choice between leadscrew or lever feed through a
rack-and-pinion drive for the X-axis feed. And -- there are a pair of
micrometer stops which can be set up to restrict the X-axis travel
rather precisely. Nice for certain forms of production work.

I've seen pictures, but never met one in person. What do they weigh?

About 1100 pounds. It comes with a gearhead three-phase motor,
so you would need a VFD or a rotary converter to run it. I can't see
swapping in any other motor. Lots of cast iron in the base, the knee,
and the table. the head is mounted to the side of the column via a
dovetail, and there is a lever connected to a rack-and-quadrant gear
arrangement to move the head up and down. There is a lever between the
motor and the head pivoted in the middle of the column, so when the
head goes up, the motor goes down, maintaining a constant spacing and
thus constant belt tension. The really old ones have 1" shafts on both
the motor and the quill, and the pulleys are double groove per speed,
two speeds, and to get the other two speeds, you had to interchange the
motor pulley with the spindle pulley.

The later ones had a single belt instead of double, and five
steps so you had a pretty good range of speeds. I've adapted the later
pulleys to mine -- but I don't have the larger bore for a bigger drawbar
which the newer ones had. I had to make my own mounting ring for the
vertical head. But mine was a *very* old one. Both the horizontal head
and the vertical adaptor use 40-taper NTMB holders and arbors.

Enjoy,
DoN.

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