(this one’s a little long but hopefully the pay off will
be of use to you )

Talking wood? This guy’s inhaled too much sawdust!!!

OK, how about - wood communicates? The difficulty
is understanding what it’s communicating.

Let me explain with an example.

I’m turning a green walnut branch. I’ve gotten
through the bark and the cambium layer into
the sapwood. I can recognize when the roughing
gouge encounters a hidden knot or heartwood
bump just below the surface because the tool
will bump there - just a little - before I can
actually see the source of the bump. If there’s
some punky wood just under the surface, that
will also be communicated - a different kind of
bump - a soft bumping.

But sometimes interpretting what the wood is
“saying” is more difficult to interpret. I was
just working into the heartwood when I heard,
rather than felt, an unfamiliar sound - a soft
clicking. I stopped the lathe to investigate.
Nothng was obvious. Turned some more and
heard the same sound again, but over a longer
area of the piece. Stopped the lathe and
checked things out again. Still no obvious
source for the sound.

Now I’m taking light shearing cuts and listening
carefully. The sound changes from a clicking
to what seems the familiar flapping of a torn
piece hitting the closely placed tool rest. I
stop the lathe, planning on removing the
errant piece. Nothing there to remove. Guess
I’m getting paranoid.

But a little more turning and the flapping
sound returns. This time when I look for
the source of the problem I look a little
more closely. In the suspect area, the
surface is different than on either side
of the last pass. It’s rough, not smooth,
like the surface had rubbed the tool rest.
Though it’s close to the tool rest, it isn’t
making contact with the tool rest - while
the lathe is off.

I check that the piece is secured between
the spur drive and the tail head. But that
wasn’t the source. Hmmm.

A few more passes and more of the under
lying heartwood is exposed. And the flapping
sound gets louder. A deeper pass and the
source becomes apparent. There’s a subtle
tear/split in the heartwood, running parallel to
the long axis - but only for three or four inches.
The centripital force (you’re thinking “shouldn’t
that be centrifical force?” No, because that’s
a misnomer. What we call “centrifical force” is
actually “centripital force” but we’ll let that go)
opens up the tear, just a little, and the pressure
of the tool closes it. The result is a flapping
sound.

The wood had been trying to tell me there was
a tear below the surface but I wasn’t able to
interpret what it was telling me. Had I made a
deep cut pass I might have had a nasty tearout
or catch.

So now I have another “word” to add to my “wood
language” dictionary, and so do you. Wood does
talk to you. But you have to use all your senses,
smell, touch, hearing and taste sometimes or
you’ll miss what it’s trying to tell you.

Just something to tuck away in your bag of tricks
- or not.

charlie b

so much to learn, so much fun learning it

"charlie b" wrote in message
...
So now I have another "word" to add to my "wood
language" dictionary, and so do you. Wood does
talk to you. But you have to use all your senses,
smell, touch, hearing and taste sometimes or
you'll miss what it's trying to tell you.

Just something to tuck away in your bag of tricks
- or not.

One of the reasons why slapping on the tunes (then there's the dangling
wires, but that's another danger) isn't the best thing to do while turning.
At the first "click" you should be checking to find out what's about to
shred the piece. Burls, with all the internal surprises, are my favorite.

"charlie b" wrote in message
...

The centripital force (you're thinking "shouldn't
that be centrifical force?" No, because that's
a misnomer. What we call "centrifical force" is
actually "centripital force"


Wouldn't that be "tangential acceleration"?-)

Bjarte

Bjarte Runderheim wrote:


"charlie b" wrote in message
...

The centripital force (you're thinking "shouldn't
that be centrifical force?" No, because that's
a misnomer. What we call "centrifical force" is
actually "centripital force"


Wouldn't that be "tangential acceleration"?-)

Centrifugal force is the reaction force produced by an object undergoing
centripetal acceleration if one wants to be pedantic.

Bjarte

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)