He certainly has options available with his existing tooling/accessories.

Double-sided tape (not the thick stuff, with foam in the center) is somewhat
commonly available in 1/2" and 2" widths. I've seen 1/2" DST available in
stores that stock winterizing/weatherproofing products as a method of
applying plastic film to window openings, and the 2" width is often
available as a product for working with carpeting.

Enco and various other suppliers generally have DST in larger length rolls,
and made by 3M.
The DST method of securing thin workpieces should be adequate (it's a fairly
common shop practice) as long as the workpieces don't get too hot, as the
adhesive grip will weaken at elevated temperatures.

As Michael has mentioned that he has (I think) 2 faceplates available, each
of them could be adapted for sundial plate machining, if they're not
frequently used for other purposes.

I think we've been discussing the generic 9x20 lathe in this instance. My
experience with owning one of these light duty lathes, is that it doesn't
take much to induce chatter with these models.
That's why I've been making suggestions for faceplate or the supplied 4-jaw
chuck for turning/facing the sundial plates, as the working diameters are
relatively large for these lathes.
These existing accessories will keep the workpieces close to the spindle
nose bearing, which will likely minimize the risk of chatter, whereas I
believe the addition of a new chuck will likely increase the likelyhood of
chatter due to the extended overhang distance from the spindle nose bearing.

Machining these sundial workpieces seems as though it would be very much
like working a bowl on a wood lathe, since the workpiece is free-hanging
from the spindle/workholding accessory.

Protecting the precision lathe parts from wood debris isn't very troublesome
by just using some disposable material such as newspaper or aluminum foil
and possibly some masking tape. Paper products covering the lathe bed
wouldn't be especially suitable if hot metal chips are present.

--
WB
..........


"Jim Wilkins" wrote in message
...
On Dec 18, 12:58 am, "Wild_Bill" wrote:
Another option might be to fabricate some better/new jaws for your
existing
"basic" 4-jaw chuck that comes with 9x20 lathes, or to modify the present
jaws.
...

I don't know exactly what your lathe is like with and can only
extrapolate from industrial lathe methods that may not be appropriate
on a simpler hobby lathe.

Considering the problems with small pie chuck jaws I still think my
earlier suggestion of a wooden block on a faceplate may be worth the
nuisance it brings.That was to glue the disk blank to the wood and
screw on temporary clamps to either the OD or ID while turning the
other. The glue mostly has to hold the disk in place while you move
the clamps.

You could make dog clamps to keep it centered while facing. These are
blocks that attach to the faceplate, with screws at a right angle to
press in radially on the work. The other clamps are woodscrews with
steel and faucet washers.

Standard practice for turning wood bowls is to glue the blank to a
wood faceplate overlay with one layer of newspaper in the glue joint.
It holds very well and then breaks cleanly when you tap a chisel into
the joint.

jsw