On Sep 27, 5:39*pm, "Michael Koblic" wrote:
----- Original Message -----
From: "Jim Wilkins"

Newsgroups: rec.crafts.metalworking
Sent: Saturday, September 27, 2008 5:41 AM
Subject: Economics of transmission

A rotary sander or buffer will turn the work piece all by itself, you
don't need to drive it separately, just allow it to rotate. You
control the speed by the angle of contact.

Do I understand you right? You are sanding/polishing as you driving the
object in one operation?

I wonder if that would clean up the edges, too. I
got a 3-jaw chuck which I could get to spin on something while keeping the
work in contact with a stationary disk sander. Now that would be brilliant!

I was cleaning up the edge, trying to cut a flat wider than the
bandsaw blade in the unworn tread of the front tire. The grinder was
cutting crosswise at perhaps a 20 to 30 degree angle. When it cut
straight across the wheel slowed and stopped, when it ran
circumferentially the wheel sped up gradually to 80 MPH. It would be
difficult to true up a disk that was out of round with a hand-held
tool this way unless there was a tool rest, which the bandsaw frame
provided.

Otherwise I can see how polishing could be done at 700 rpm but I was not
sure about ruing up the edges - I thought that would have to be done
somewhere around 60 rpm.

However all of that is on hold as an opportunity has presented itself today
to look at a real lathe (see my other today's post - what to look for before
parting with cash!)

Michael Koblic,
Campbell River, BC

A lathe like that should let you make a large polishing turntable
pretty easily. According to my CAD drawing of water pipe, 3/4" pipe is
1.050 OD. You could turn a piece down to 1.00" to take trailer wheel
bearings, screw on a floor flange and some plywood, and have your
turntable. Pillow block bearings would be easier to mount if you can
find some. http://www.baileynet.com

I need to get busy on my lathe now. I bought a 1 ton I-beam trolley
from HF and discovered that its wheels won't fit into 3" channel iron,
so I need to turn them down a little.

Jim Wilkins