"buck" wrote in message news:...
I asked this question a month ago or so and opinions varied from..... It
should never happen- to the tool rest will save you- to wear a complete
face
mask- to hide under the bed.... I decided to wear a full rubber dust mask
and safety glasses.... and keep checking the lock handles.


"Anonymous" wrote in message
.. .
On Mon, 29 Nov 2004 10:45:14 -0500, J. Clarke wrote:

George wrote:

Oversimplification, I'll admit. The initial "hit" which I'm going to
presume will come from a tool, is the only one which doesn't
necessarily
worry about incidence/reflection, etc. That's why it should be
forced
down by cutting position.

And the theory I learned - non quantum - was that the energy of a
collision
divided equally on the hitter and hitee. How about that scientific
for
scientific terminology!

That's strictly true only if the "hitter" and the "hittee" are
identical.
In the case where the "hittee" is much more massive than the "hitter",
if
the collision is perfectly elastic the hitter rebounds with nearly all
of
its original energy.

Generally speaking a well-mounted lathe can be considered an immovable
object for the purpose of making a first approximation of the energy
of
a
rebounding object. Of course the collision is not generally perfectly
elastic, how far it deviates depends on what you're turning and what
it
hits--a piece of balsa will generally deform a lot more than a piece
of
lignum vitae. Unfortunately, that also means that in general the
heavier
the wood, the more energy it's going to retain.

Elasticity? I'd rather do inductance calculations....

"Martin Rost" rostmartin @ hot mail . com wrote in message
...
George,
Theory is great, but there is a rotational component to the piece,
so
if
it
comes loose and contacts something it will tend to climb up it.
Where
did Newton say anything about every hit takes half the hurt
potential
away? There are elastic and inelastic collisions, in an inelastic
collision with one object moving and one anchored, there is a change
in
direction of the
one object with minimal change is speed. As an example drop a golf
ball
on
to a hard surface, it will bounce up more than half the height it
was
dropped from.
Your suggestions for turning safely should be heeded none the
less.
Martin

Have you seen "An Unfortunate Incident?" It may answer the question
posed
in the subject of this thread.
http://www.enter.net/~ultradad/incident.html