Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx

Think back to your Physics class. It will go opposite the last force it
encounters. Keep your toolrest between yourself and the piece, and cut
slightly above centerline.

"buck" wrote in message
rvers.com...
Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx

"buck" skrev i melding
rvers.com...
Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx

A good sized pece of wood at too high speed _has_ been known to
kill people.
From personal experience I saw such a piece of wood careen around
my fathers shop, and kill his zest for woodturning. (Plus it gave him
torn skin and hurt pride.)

Someone could (maybe) calculate the energy in the 2by24 you describe?
I'm not that good with numbers.

Bjarte

Here in the UK it is "Sods Law" that the piece will fly off the lathe
in the most dangerous trajectory possible.

Like buttered toast always landing face down on the floor.

In all the years that I have practiced turning dangerous pieces of
timber, not once have they landed safely out of harms way. I am so
happy that because of my slow reaction times I insist on wearing my
full face visor otherwise my features would have been remodelled
several times over.

Do not take the chance, expect the worst!


Regards,
Peter Charles Fagg
Freshwater, Isle of Wight,
United Kingdom.
www.petersplatters.co.uk
Each can do but little!
But if each DID that little,
ALL would be done!

"Peter Charles Fagg" wrote in message

Here in the UK it is "Sods Law" that the piece will fly off the lathe
in the most dangerous trajectory possible.

Like buttered toast always landing face down on the floor.

Hmmmm. Wasn't Murphy and Englishman?

Max

Maxprop wrote:
Hmmmm. Wasn't Murphy and Englishman?

MURPHY!? Irish, surely.

Dave in Fairfax
--
Dave Leader
reply-to doesn't work
use:
daveldr at att dot net
American Association of Woodturners
http://www.woodturner.org
Capital Area Woodturners
http://www.capwoodturners.org/
PATINA
http://www.Patinatools.org/

"Peter Charles Fagg" wrote in message
m...
Here in the UK it is "Sods Law" that the piece will fly off the lathe
in the most dangerous trajectory possible.
==================================
Peter,
Here in the other side of the pond, that's known as "Murphy's Law".
"O'Toole's Corollary" says Murphy is an optomist! {:-)

Ken Moon
Webberville, TX

"buck" wrote in message
rvers.com...
Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx


There is no predicting the direction. You may have observed that some
turning respirator gear looks like a hard hat for good reason. I wouldn't
consider turning without a full-face shield as a minimum.
My biggest disaster was a piece held by one end in a chuck (it should have
had the tailstock as well) that went up hit the ceiling, then a lamp on the
way down before contacting the band of my face-shield. Fortunately I wasn't
injured but it got my attention in a hurry. I think that a spindle is less
likely to come loose and fly since if they loosen you notice it by poor or
lack of drive.

Other woodworking tools can maim you, a lathe can kill you!
Billh

I've had three bowl chunks and one spindle hit me square in the face.
On all four occasions I was wearing my face shield. Three of the
times the shield was actually down.

Now I ALWAYS wear a face shield....down.

Jack Savona


"buck" wrote in message ervers.com...
Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx

Well, an Englishman name of Newton disagrees. He says opposite the impact.
That's why you keep your toolrest close to make sure it hits there before it
enters a navel battle with you, and cut above center so a catch knocks it
down. From that point on, everything it hits, according to Newton, takes
half the hurt potential away in the impact.

More interesting is that doubling the speed equals four times the initial
energy, which goes back to an answer I gave earlier about spindle turnings -
slower is _much_ safer - so turn at a speed commensurate with your best
edge, and don't be tempted to get more energy in the equation to compensate
for a dulling edge or a poor presentation. Change the presentation or
refresh the edge. Fortunately I don't have an instant speedup capability on
my old iron beast, so it's actually easier to freshen the edge.

"billh" wrote in message
. ..


There is no predicting the direction.

IME, 99% of the time spindles drop right on the bed of the lathe,
shortly after hitting the toolrest. There are many other good reasons to
keep the toolrest close in. I have had chunks fly by when a chunk split
off the workpiece, but mostly it's been pretty boring.

A good high-impact face sheild is a good idea, regardless.

If it helps with your peace of mind, you can also get one of those
wierd-looking cage guards for spindles. If spindles were all you did, it
might not be too annoying.

As others have noted, keep the speed reasonable, which keeps the energy
down.

--
Cats, Coffee, Chocolate...vices to live by

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

"George" george@least wrote in message
...
Well, an Englishman name of Newton disagrees. He says opposite the
impact.
That's why you keep your toolrest close to make sure it hits there before
it
enters a navel battle with you, and cut above center so a catch knocks it
down. From that point on, everything it hits, according to Newton, takes
half the hurt potential away in the impact.

More interesting is that doubling the speed equals four times the initial
energy, which goes back to an answer I gave earlier about spindle
turnings -
slower is _much_ safer - so turn at a speed commensurate with your best
edge, and don't be tempted to get more energy in the equation to
compensate
for a dulling edge or a poor presentation. Change the presentation or
refresh the edge. Fortunately I don't have an instant speedup capability
on
my old iron beast, so it's actually easier to freshen the edge.

"billh" wrote in message
. ..


There is no predicting the direction.

buck wrote:
Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.

I think it would be more useful to ask 'what would cause the piece to
come off the lathe in the first place'. If you are having spindles come
loose when turned between centers, seems to me like something is
seriously wrong. I can't think of many scenarios:

- the spur point cuts a groove through the end of the wood if you have a
catch. Most likely if the wood is soft or the spur point is not driven
far enough into the wood.
- the wood breaks, possibly if the grain is not straight, has a knot or
other defect, or if it is abused by the turner
- the tailstock and quill are not locked in place.

If in doubt, check everything before starting the lathe, stop at
intervals during the job and check again. By all means wear a face
shield just in case, but if you really feel that the wood is going to
come off the lathe, tackle some smaller and simpler jobs until you have
gained more experience and confidence.

Seatbelts and airbags are no substitute for good driving and proper
training.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
Wedding Favors ~ Artisan Crafted Gifts ~ One-of-a-Kind Woodturning

On Mon, 22 Nov 2004 08:13:44 -0700, "buck"
wrote:

Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx

I've never been hit by one... had a few long pieces like that drop off
and get dinged..
One bowl came off and rolled around the shop for a while.. lol
seems like they went down and away from me before hitting something
and bouncing..

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!

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

Hey, Thanks to everyone for your input. I now have a much better idea of
what to do, what not to do, and what to expect if I should screw up. I knew
I came to the right place.


"buck" wrote in message
rvers.com...
Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx

On Tue, 23 Nov 2004 21:39:01 -0700, "buck"
wrote:
ok, I'll admit it...
My initial instinct when anything "clunks" or doesn't sound right is
to flinch away from the lathe and turn my back on it..
catching a flying cylinder on the butt is embarrassing, but catching
it on your head or face can ruin your whole day..

Hey, Thanks to everyone for your input. I now have a much better idea of
what to do, what not to do, and what to expect if I should screw up. I knew
I came to the right place.


"buck" wrote in message
ervers.com...
Just curious as what to expect if a 2" square x 24" piece of stock should
come loose from lathe at 2000 rpm....... Would it just fall to the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all over
the place but not sure about a thinner piece when doing spindle work.
-thanx

My worst case of flying timbers:
Mounted a 6 x 6 x 50" piece and forgot to turn my speed down.
The piece I was turning before this was at 2200 RPM.
When I hit the start button the blank started to spin and it tore
loose at the head stock, I knew that I had screwed up
as soon as I turned
the lathe on, but it was to late. It took out an 8 foot fluoresent
light that was about 9 feet above my head, the blank then hit my work
bench that was about
4 feet away and smashed a 3/4 X 2" piece of Maple that was used as an
edge band
on my bench. It then landed on the concrete floor and bounced and
danced
for a while. I was un-injured in the mishap.
I never stand in front of the lathe when starting it up.
I now always always always check my speed before starting the lathe.
You should have seen the look on a co-workers face, he was walking
by my area when this happened, his eyes looked like two plates.LOL
Jim

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

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

mac davis wrote:

On Tue, 23 Nov 2004 21:39:01 -0700, "buck"
wrote:
ok, I'll admit it...
My initial instinct when anything "clunks" or doesn't sound right is
to flinch away from the lathe and turn my back on it..
catching a flying cylinder on the butt is embarrassing, but catching
it on your head or face can ruin your whole day..

Just remember that catching it in a kidney is no fun either.

Hey, Thanks to everyone for your input. I now have a much better idea of
what to do, what not to do, and what to expect if I should screw up. I
knew I came to the right place.


"buck" wrote in message
servers.com...
Just curious as what to expect if a 2" square x 24" piece of stock
should come loose from lathe at 2000 rpm....... Would it just fall to
the
workbench..... Go flying across the room..... or lodge into my head? I
would imagine that when you turn bowls things can kind of explode all
over the place but not sure about a thinner piece when doing spindle
work. -thanx




--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

On Mon, 29 Nov 2004 10:46:57 -0500, "J. Clarke"
wrote:

mac davis wrote:

On Tue, 23 Nov 2004 21:39:01 -0700, "buck"
wrote:
ok, I'll admit it...
My initial instinct when anything "clunks" or doesn't sound right is
to flinch away from the lathe and turn my back on it..
catching a flying cylinder on the butt is embarrassing, but catching
it on your head or face can ruin your whole day..

Just remember that catching it in a kidney is no fun either.

very true... though I think it would have to go through the tool rest
to hit me that low, loose things from the lathe, like footballs, can
take some pretty weird bounces..

Maybe it's just my instinctive reaction.. to protect my face/head..

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

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

"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