On Aug 28, 11:51 pm, "Michael Koblic" wrote:
"Jim Wilkins" wrote in message

Some "thoughts" would make your hair stand on end...:-)

What little hair is left... :-( (that's a beard, I grow it wherever
I still can)
I've run the model shop in electronics companies and thus dealt with
the creative misadventures of clever engineers with no practical
experience.

In the end when hooked up to the live centre (which is loose on the drill
press table) the live centre was running around in a small circle
whatever I did.

A large pointed setscrew held by nuts and washers might work.

Setscrew pointed upward for the center, nuts and washers to hold it
tight in the hole.

...You can align them with a piece of wire in the chuck,...

I have re-read this about six times and I am not altogether sure that I
understood: I have no difficulty aligning the centre point of the live
centre with the centre of the spindle. However, when I chuck the gnomon and
put the opposite end on the live centre (using the supposedly centre hole I
drilled), the gnomon, being slightly out of alignment, moves the live centre
around.

http://www.lindsaybks.com/bks/advmach/index.html

Don't be put off by its age. Production techniques may have improved
dramatically since then but manual lathe operations are still the
same.

If the chuck doesn't hold the part straight you mount it between
centers and drive it with a dog.
I think a 4-sided pyramidal point held in the drill chuck is enough to
drive brass without a dog if you take light cuts. You don't need to
make the point run perfectly true as long as you mark it so you can
remove and replace the work.

How well did you learn Euclidean geometry?
The euclid works if the cross-section is truly circular.

There are constructions for centering even a triangle.
A quick shortcut I often use is to center a thin 6" flex rule across
the work by equalizing the end readings.
For example one end is at 1-1/8", the other at 4-7/8".
Hold a scriber point against the work at the 3" mark, then turn the
rule 90 degrees and repeat.
I like the style of graduations called 3R for this.

but the transfer punch/paper roll method beats it every time particularly
for small parts.

That's a good idea I hadn't seen before. Then again I have a collet
lathe which is the perfect machine for making small round parts. Mine
would be a little more perfect if it hadn't been abused in trade
school. A small lathe with a 3-jaw chuck is close. http://www.mini-lathe.com/

Maybe with a centre drill you do not need to punch? Am I right in that?

See the center/spot/stub drill thread. With less rigid equipment like
your drill press and my 50-year-old milling machine you have to learn
what works and what doesn't. The punch mark is to align the drill bit
with your hand layout since it's very difficult to position the center
of the drill bit directly.

Jim Wilkins