wrote in message
...
On Wed, 15 Jun 2011 11:15:56 -0700, Tim Wescott
wrote:

Think prop spinner for a model airplane (is this sounding familiar?)

Assuming that I'm not turning from solid (oh, it sure is!), how hard is
this going to be on a Smithy-sized lathe (7" swing over the ways, cheap
Chinese construction). I'm thinking that I'd use soft aluminum, no
thicker than 50 mil and probably more like 30 or 40.

I've never spun metal before, but I've seen videos so I know I'll be
able to do it with hand-made tools, like a pro, the very first time.

While we're on the subject -- how do you spin a piece that's rounded on
the end? Make a dimple in your sheet, then spin down from there?
You've got to have some surface area on the tail stock, don't you?
Tim-
You're gonna have to first turn the spud that supports your piece to
the inside shape. Then hold the piece to to the spud with a hardwood
pusher. Push on this pusher with a live center of course. Once the
pusher is spinning cut away enough of it to get enough clearance for
your spinning tools. BTW, pieces that are long in relation to their
diameter are hard to spin. You will probably need to anneal the piece
a couple times. Good Luck.
Eric

Full disclosu I've never done this, but I've watched.

A piece like that likely would be much easier to spin if you start with a
tube, and work it down over a steel mandrel. Use a lot of pressure on the
tool (you may need a wheel-type) to shrink it down uniformly as you progress
toward the point.

--
Ed Huntress