Prometheus wrote:


Of course, any helpful tips on eliminating that static charge would
probably convince me to use the sucker at all times.


Try one of the static cling sprays designed for laundry care.

--
Jack Novak
Buffalo, NY - USA

"Prometheus" wrote in message
...
I've got one that is clear, lightweight and comfortable, but it builds
up so much static electricity that is sucks every bit of dust it can
hold migrates to it immediately, and make it hard to see.

Wipe it down with a dryer sheet.

In article , Prometheus wrote:

It's strong enough- unless you're doing something really crazy, like
turning wood with live ammunition in it. Think about it for a minute-
the rotational force of the piece isn't the only thing that affects
how it's going to fly off if something breaks or is not held
correctly. Gravity has it's say as well- and from previous exerience
when I got my first chuck, anything that could possibly be heavy
enough to break the sheild drops just as fast or faster than it is
moving towards you.

The laws of physics dictate quite the opposite, in fact. To begin with, the
mass of an object has absolutely nothing to do with how fast it falls (as was
famously demonstrated by Galileo some five centuries ago).

Most heavy things will fall fast, then roll along
the floor- not shoot at you like a cannonball.

Again -- the velocity of a falling object is completely independent of its
mass.

Which direction it goes depends mostly on which direction it's moving when it
comes loose (e.g. on the back side of the work, moving upward -- it's gonna
launch!); at even modest rotational speeds, the velocity of the circumference
of a large workpiece exceeds anything that would be imparted by gravity in the
very short distance between spindle or faceplate and the shop floor.

Example: 10-in diameter workpiece rotating at 500 rpm; lathe center at 42"
above the floor.

The edge of the workpiece is moving at (10 pi * 500) inches per minute =
almost 22 feet per second -- but an object falling only 42" doesn't attain a
velocity of quite 15 fps before it hits the floor.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On 30 Nov 2006 11:42:05 -0800, wrote:

If you are intelligent enough to think about what you are doing, you
won't get hurt. So what does that mean in your world? The flip side
of your hypothesis is the people that should expect to get hurt are the
ones that won't think, can't think, aren't able to think, or don't know
how to think? Only non-thinkers get hurt at the lathe?

In the vast majority of cases, yes.

So accidents don't happen, much less bad accidents don't happen to
those that think. All you have to do is "thinking man" and you have
"no reason" to worry about being hurt while using the lathe.

Going by the definition of 'accident' that you give, 'unforseen' and
'unplanned' have no meaning to someone who understands the risks and
plans for them. If you're an idiot and don't know what you're doing
and don't plan for safety and failure, then you're going to get
injured a lot more often than someone who approaches the task
intelligently and rationally.

On Sun, 03 Dec 2006 02:38:29 -0600, Prometheus
wrote:

I've got one that is clear, lightweight and comfortable, but it builds
up so much static electricity that is sucks every bit of dust it can
hold migrates to it immediately, and make it hard to see.

There are all kinds of anti-static sprays you can buy, or you can just
use an anti-static dryer sheet, although it probably won't last nearly
as long as some of the products specifically intended for eliminating
static cling.

"Doug Miller" wrote in message
t...
In article , Prometheus
wrote:

It's strong enough- unless you're doing something really crazy, like
turning wood with live ammunition in it. Think about it for a minute-
the rotational force of the piece isn't the only thing that affects
how it's going to fly off if something breaks or is not held
correctly. Gravity has it's say as well- and from previous exerience
when I got my first chuck, anything that could possibly be heavy
enough to break the sheild drops just as fast or faster than it is
moving towards you.

The laws of physics dictate quite the opposite, in fact. To begin with,
the
mass of an object has absolutely nothing to do with how fast it falls (as
was
famously demonstrated by Galileo some five centuries ago).

Think he's talking about the standard 1/2 MV sq inelastic collision
accomplishing some heavy deceleration. Since we're pretty much confined to
earth with our turnings, the M is going to be equal to weight, and it's part
of that equation.

Rather not have a shield. Cuts down on the number of random directions a
piece might take on the ricochet. Just stand out of the zone and let 'er
fly if she cares, though with a modicum of effort no reason it should.

Most machine injuries I've seen contained some element of pursuit of the
piece rather than letting it fly where it would predictably go and the
injured should not be. Buck twenty nine worth of walnut becomes a 1500
dollar ambulance ride and that's only the beginning.

"Doug Miller" wrote in message
t...
In article , Prometheus
wrote:

It's strong enough- unless you're doing something really crazy, like
turning wood with live ammunition in it. Think about it for a minute-
the rotational force of the piece isn't the only thing that affects
how it's going to fly off if something breaks or is not held
correctly. Gravity has it's say as well- and from previous exerience
when I got my first chuck, anything that could possibly be heavy
enough to break the sheild drops just as fast or faster than it is
moving towards you.

The laws of physics dictate quite the opposite, in fact. To begin with,
the
mass of an object has absolutely nothing to do with how fast it falls (as
was
famously demonstrated by Galileo some five centuries ago).

Most heavy things will fall fast, then roll along
the floor- not shoot at you like a cannonball.

Again -- the velocity of a falling object is completely independent of its
mass.

Which direction it goes depends mostly on which direction it's moving when
it
comes loose (e.g. on the back side of the work, moving upward -- it's
gonna
launch!); at even modest rotational speeds, the velocity of the
circumference
of a large workpiece exceeds anything that would be imparted by gravity in
the
very short distance between spindle or faceplate and the shop floor.

Example: 10-in diameter workpiece rotating at 500 rpm; lathe center at 42"
above the floor.

The edge of the workpiece is moving at (10 pi * 500) inches per minute =
almost 22 feet per second -- but an object falling only 42" doesn't attain
a
velocity of quite 15 fps before it hits the floor.

Your physics is certainly correct; gravity only has a split second to act on
the object, so imparts very little velocity on it. (mv=ft and all that...)
Yet intuitively it seems that things should tend to fall down rather than
up. Yes, I know intuition is wrong half the time, but still...

It has been a very very long time since I did any of this. f from the
rotation is proportionate to the m of the object in question, so the mass
doesn't matter there either.

badger.badger wrote:

Of course, any helpful tips on eliminating that static charge would
probably convince me to use the sucker at all times.

RainX ?
--

Sometime they'll give a war and nobody will come.

Carl Sandburg (1878 - 1967), The People, Yes (1936)

Doug Miller wrote:

Again -- the velocity of a falling object is completely independent of its
mass.

Not at all - the velocity of _freely_ falling objects is independent of
mass, but lathe turnings aren't usually freely falling -- they're
spinning objects in passing contact with some fixed point that can
impart a force to them. If they're balanced and they fall free from the
chuck then it's no problem - if they catch on the way down, it can get
hairy.

(PS Toller - if you're going to post trivial equations, at least get a
schoolkid to check them first)

In article om, "Andy Dingley " wrote:

Doug Miller wrote:

Again -- the velocity of a falling object is completely independent of its
mass.

Not at all

What do you mean, "not at all"? That was demonstrated by Galileo about five
hundred years ago.

- the velocity of _freely_ falling objects is independent of
mass, but lathe turnings aren't usually freely falling --

They are the moment they come loose from the lathe, which is the issue at
hand. As long as they stay attached, they are not falling objects, and
therefore not relevant to the discussion.

they're
spinning objects in passing contact with some fixed point that can
impart a force to them.

Yes, and that's one of the points I was making -- the force imparted to them
by the lathe is, in most circumstances, of greater magnitude than that
imparted by gravity.

If they're balanced and they fall free from the
chuck then it's no problem - if they catch on the way down, it can get
hairy.

If balanced, sure -- but what if something *breaks*? Then, it's no longer
balanced -- and the direction that broken-off piece moves depends on the
direction it was moving when it came free, and has *nothing* to do with its
mass.

Also note that a perfectly balanced lightweight piece that simply comes loose
will drop straight down, too, just like a perfectly balanced heavy one that
simply comes loose.

The behavior of falling objects in a gravity field is completely independent
of their mass (except to the extent that objects with very low *density* will
fall more slowly due to aerodynamic effects). In vacuum, a feather and a stone
fall at the same rate -- and even in air, there is no difference discenible
without the use of laboratory equipment between the velocity of falling stones
of, say, 1 kg and 10 kg, when dropped from the same height.

Whether a chunk of wood that comes loose from a lathe goes up, down, or
sideways has NOTHING to do with its mass.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On Sun, 03 Dec 2006 18:06:47 GMT, (Doug Miller)
wrote:

In article , Prometheus wrote:

It's strong enough- unless you're doing something really crazy, like
turning wood with live ammunition in it. Think about it for a minute-
the rotational force of the piece isn't the only thing that affects
how it's going to fly off if something breaks or is not held
correctly. Gravity has it's say as well- and from previous exerience
when I got my first chuck, anything that could possibly be heavy
enough to break the sheild drops just as fast or faster than it is
moving towards you.

The laws of physics dictate quite the opposite, in fact. To begin with, the
mass of an object has absolutely nothing to do with how fast it falls (as was
famously demonstrated by Galileo some five centuries ago).

I'll grant you this one, as I managed to whack myself square in the
forehead with a blank earlier this evening. Didn't fly straight off,
though- it rolled up the tool, up my arm, and then popped up when I
reflexively yanked back and straightened my arm. Didn't feel nice...
but it was an eloquent rebuttal to what I wrote above!

On 4 Dec 2006 03:02:12 -0800, "Andy Dingley "
wrote:


Doug Miller wrote:

Again -- the velocity of a falling object is completely independent of its
mass.

Not at all - the velocity of _freely_ falling objects is independent of
mass, but lathe turnings aren't usually freely falling -- they're
spinning objects in passing contact with some fixed point that can
impart a force to them. If they're balanced and they fall free from the
chuck then it's no problem - if they catch on the way down, it can get
hairy.

Yep. I've got a bruise on the noggin that says you're right.
Previous experiences with the chuck letting go were mostly right after
mounting, and didn't involve a cutting tool.