"Tim Wescott" wrote in message
...
On Wed, 04 Jan 2017 23:58:56 +0000, DoN. Nichols wrote:


So, I wonder if it would have been worthwhile to turn your taper,
and
then run a whetstone over it to smooth it out on the lathe? It's
kinda
redneck, but might work out well if you had a good touch (and a flat
whetstone).

Tim Wescott

I turned two cast iron spheres (with stems) by cutting steps according
to a spreadsheet calculation and smoothing then with a file. The
spheres are the balls in ball-and-socket joints, running in plywood
sockets so they don't have to be perfect.

It was easy to file until the steps almost disappeared. They
contrasted well enough with the filed surface and their remaining
width was a good guide.

I roughed it out quickly by setting the step size large and ball
radius oversized, then reduced both for the finish pass. The same
spreadsheet defined the sockets.

-jsw