On 21 Dec 2005 19:54:43 -0800, "Bernard Arnest"
wrote:

I'm interested first in machining a ball vise for engraving,

Never make anything you can get from a scrapyard. It'll be cheaper, and
it'll probably be better.

Ball vices are around. More commonly you can find a ball clamp, and a
vice, and introduce them yourself.

If you do want to make a ball vice, then don't try making the ball.
Balls come from ball factories - they're a pain to make, there's a trade
in them, so go find one. Besides which, the idea of buying steel for
over $/lb makes me faint. If you ever do need something big and hefty
(an armourer's anvil stake for instance) then this is why the good Ford
gave us scrapyards, and he gave the scrapyards heavy crankshafts and
gave us angle grinders. It's a sin to buy new steel just to machine away
most of it.

more ambitiously, making my own rose engine.

That's insanely ambitious. So before you do it, you really do need to
make a few simple projects first, like the odd Difference Engine or two.
I don't want to discourage you, but it really will be quicker and easier
if you begin by making some moderately complex things first - you'll
simply be _quicker_ with a bit of practice.

There's also the issue that all you've seen first is lathe turning. So
at the moment, every problem looks like a turning problem. This is a
very inefficient way to work - why turn a ball from bar when you could
cast it instead? Why machine from solid for something you can fabricate
by welding? The more techniques you learn, the more avenues you have
for how to make something.

As far as making the complex cammy parts of a rose engine, then I'd look
very hard at CNC, quite possibly CNC milling on a rotary table. You dont
have to make a "CNC rose engine" (although the idea is tempting), but
certainly CNC is a good way to make some of the complex parts.