On Fri, 17 Feb 2006 16:38:12 GMT, "Boris Beizer"
wrote:


"Eric R Snow" wrote in message
.. .
On Thu, 16 Feb 2006 23:08:00 GMT, John Doe
wrote:

What you should do is hold
the part in your left hand, but have it inverted so that the cutting
action takes place on the bottom of the part and the chips fly away
from you.

Wow, Eric. You must have some of them Superman genes that gives you X-ray
vision that lets you to see through the part to gauge how much you are
cutting off. Nope, I have it wrong. You are right after all. The idea is
to hold the work over your head, Then the chips fly away from you and you
can see the cut as it progresses. Maybe one should stand on their head???
The reason for the rotation direction as said elsewhere, is that not
only drills, but burrs, reamers and other cutting tools are designed for
that direction. Futhermore, arbors for cut-off discs, grinding stones,
abrasive discs, etc. would all come undone with counter-clockwise rotation.
So it's not just the motor, but much of the tooling that has to be made
left-handed.
The direction choice probably originated with ancient lathes. You
use the right hand to control the tool and turn the lathe with the left
hand, pulling the wheel toward's you. The idea is that the work should
force the tool against the ways rather than turning away from you and
thereby forcing the tool away from the ways and greatly increasing the
likelyhood of chatter. Now once you have the lathe set up that way, with
the headstock on the left, you could still opt to make right-hand or
left-hand threads (as do the Germans). With a right-hand thread, the work
is pushed into the chuck (towards the headstock). With a left-hand thread,
the work is pulled out of the chuck. So the right-hand thread is
inherently a safer and more rigid set up. Once you have a dominance of
right-hand threads on things, the clockwise rotation is set.
This may be yet another just-so story, but it makes sense to me.

As for the "dust in your face" problem. I've got three flex shaft
machines. I've been using them for years. I've never had a problem with
dust in my face from the rotation direction. On those very rare occassions
where it was potentially problematic, I've used my face shield. Perhaps
the poster's problem is not with his tool, but with his glasses. Your nose
just shouldn't be that close to the work.

Boris
Greetings Boris,
Yes I do have x-ray visioin. How'd you know? Actually, my post above
was tongue-in-cheek. I should have said so. It's hard to get across
tone of voice in text.
ERS